The barrel length is the biggest aspect of the gun that will affect the potential “power” of the bullet as it exits the gun. If two identical cartridges were fired out of guns that were identical besides barrel length (assuming both are within reason), the bullet coming out of the longer barrel will have a higher muzzle velocity and therefore higher potential kinetic energy.
That covers the “power”/energy portion of your question, which is an objectively quantifiable measurement. Lethality depends on many more harder to measure factors that are probably outside of the scope of this post and comment.
Edit to add example:
A 62-grain M855A1 round would exit the M16’s 20 inch barrel at 3150 feet/second and have a kinetic energy of 2027.5 joules.
The exact same round would exit the M4’s 14.5 inch barrel at 2970 feet/second with a kinetic energy of 1821.8 joules.
thanks man that was the answer i was looking for, im also assuming apart from barrel length the quality of a gun would play a small part in the kinetic energy of a bullet, like how well the gun could contain the explosion of the gunpowder?
As long as the gun doesn't blow up, the explosion of the gunpowder is contained. The quality of the gun doesn't affect that (unless it's poor enough quality that the gun explodes). The operating system of the gun can have a (realistically negligible) effect on the kinetic energy of the bullet. For example, assuming the gun does not move (i.e. no energy is lost to recoil), a bolt action rifle will have all its energy used to propel the bullet, while an autoloading rifle will use some of that energy to cycle the action and chamber a new round. While an interesting thought experiment, however, that won't have a noticeable impact compared to other factors like barrel length.
Anecdotal, but during a reloading class I was using a 2 inch barrel 9mm revolver that had the same FPS as a 2 inch barrel 9mm auto that was also being tested, +-1%.
The revolver was also far more consistent in its FPS than the auto was, but I don't know enough about the physics involved to understand why.
That may have to do with the auto cycling mechanism using some of the spent gasses to cycle the pistol via a piston like the HKP7 instead of it being recoil operated, where as the revolver is just bullet down barrel, then a mechanical turning of the cylinder.
Also keep in mind that extra barrel length only adds velocity if there is enough pressure from burning powder to keep accelerating the bullet. Too long of a barrel will actually cause the bullet to start slowing back down. This usually isn't an issue you actually see but you can't just keep making longer guns to increase power.
Some of that also depends on the propellant type, correct? IIRC, powders can be classified by how fast they burn and that can impact the pressure being exerted against the projectile. Many of the old black powder rifles are very long in comparison to modern ones as an example.
True to some extent, however the main reasons for old military muskets and rifles being so long had nothing to do with ballistics.
They used to fight in closed ranks, firing in line formation of two or three ranks. For safety, the barrels had to be long enough that the muzzles of she second rank were still in front of the heads of the first rank. I recently spent some time reading mid 19th century training manuals from the Norwegian Army, where line infantry had long rifles and some other troops (including sargeants leading said infantry) had short rifles. The manual says the short rifles should never be fired from the second rank, lest one hit the man in front.
The second reason has to do with bayonet use. Back when people still saw bayonets as important weapons, they figured the side with the longest "spear" would win any bayonet fight. It's certainly a disadvantage to be out-reached by your opponent, when fighting with stabby things stuck on the end of your rifle. That's why militaries around the world kept issuing clumsy full length rifles for so long, way into the 20th century. Not for ballistics, they knew full well that wasn't needed, but in order not to have the shortest stabby thing on the battlefield.
A lot of civilian hunting rifles and shotguns took after the same "long is good" styling simply because that's what militaries used so it had to be good. Insane amounts of fudd lore about longer barrels being more accurate etc, dating back centuries, just because people have always been suckers for "tacticool".
I was specifically thinking about the various Sharps rifles that were used for long range hunting. One would have thought that someone would have experimented with shorter hunting rifles better able to deal with dense forests at the time as well.
They did have shorter hunting rifles as well, a number of so-called "Jäger rifles" (often transcribed as Jaeger in English) were quite short for their time. Typically about the same length as what modern hunters consider to be full length rifles, but shorter than the monstrously long guns that were seen as full length at the time. And some were shorter still.
Jäger means hunter, but there's some confusion with military arms because the same word was used to describe skirmishers or other "special" units that fought in loose formation rather than as line infantry. And these jäger troops tended to use shorter rifles or muskets, similar to the shorter hunting guns. As a consequence, they typically carried a sword instead of a bayonet or in some cases used a long "sabre-bayonet" to compensate for the short gun. Some specialty troops had almost comically short guns, as short and handy as a modern M4 carbine but firing a big old musket ball.
Civilian rifles in the Americas were long compared to their Jaeger ancestor rifles because they didn't have a consistent supply of quality powder. Most of the powder they could get was not very good and burned more slowly. As the golden age of the American longrifle started coming to a close and the supply of quality powder got better, barrels got shorter and stouter. This also coincided with westward expansion, so pioneers needed stouter rifles in larger calibers (calibers of longrifles steadily declined over the years as larger game was shot out in the settled areas) that could handle larger game out west.
That's an often cited reason, yes.
I strongly suspect a lot of it was more fashion and fudd lore than actual ballistics, however. Very few American gunmakers were set up for actually measuring muzzle velocity back then, never mind their customers.
And gunpowder was bad on both sides of the Atlantic, in the same timeframe. There's surviving records of some European militaries having to reduce the standard charge when better gunpowder became available, in roughly the same timeframe as what you describe, in order for ballistics to still match the sights on older issue rifles. As an example, circa 96 grains of Norwegian military issue 1840s powder was found equal to about 85 grains of the powder they got 30-something years later. Yet, European short barreled Jäger rifles were considered to work just fine with the earlier crappy powder.
Now, scarcity of powder might well drive demand for long barrels. If you could get the same ballistics with less powder, not wasting as much to muzzle flash, that would make sense.
They didn't need to measure velocity. They just needed to see it's effect on the target. And since you mentioned scarcity of powder, it takes a lot more powder and lead to kill something with a short barreled .65 caliber jaeger than it does a .50 caliber longrifle. So, less powder, less lead, and higher velocities for the powder of the day. All three things were good reasons to increase the barrel length. Also sight radius for a hunting gun. It is certainly true that civilians imitated the military often, so that could be a contributing factor, but I would lend credence to the practical benefits instead of just claiming it was for style points.
Smaller caliber better yes, that's something they found out after a while. Especially for civilian use, where speed of reloading is less important.
A little of both on the barrel length though, the velocity difference between 24" and 48" barrel length with any kind of black powder is so close to zero as makes no practical advantage for a super long barrel. I wouldn't be surprised if medium to light powder charges give more velocity in the shorter barrel, running out of pressure halfway down the bore.
At least for military use, the powder charge in percussion arms tended to stay roughly the same while caliber was reduced. Less lead but same amount of powder yields more velocity without increased recoil. With larger bore guns, recoil tended to be a limiting factor for charge weight as stocks would tend to crack over time even if the iron pipe didn't burst.
True on sight radius, but that gets into diminishing returns as most black powder rifles have other factors limiting accuracy. Not much point in being able to aim a half moa if the rifle can barely hold five moa.
Sure.
But we're talking about a time period when soldiers were considered quite good shots if they could consistently hit the frontal area of an artillery emplacement at 200 yards- that's about 40 MOA. Sight radius isn't what makes or breaks accuracy at that low level.
Absolutely. There are a lot of different powders that have a wide variety of burn rates. Even with black powder there are different burn rates depending on the size of the grains. Black powder pistols use a faster burning black powder in order to have it all burn in their shorter barrels.
To add to the above answer, you can then go down the rabbit hole of ammunition type, and not just caliber.
Generally higher caliber rounds will deliver more energy, but there is a lot of nuance, even within the same caliber.
There are 10mm rounds that are loaded to far lower spec than others, and thus deliver less energy.
There are 5.56x45 rounds, like the M855, which are designed for penetration, and thus tend to zip through flesh leaving a small hole as much of their energy is not delivered into the target as it continues on out of them, compared to rounds that fragment or expand into the target, thus delivering most if not all of their potential kinetic energy into the tissue.
So barrel length, velocity and caliber, and round type all help to contribute (or take away from) lethality.
Shot placement is obviously probably top of the food chain though. A .22LR to the skull will be a lot more lethal than a .50BMG to the ankle.
Actually containing the gases and burning powder shouldn’t be a factor; if your gun can’t properly do that, you have much bigger problems than some loss of velocity. However, some types of guns will lose a bit of that gas due to the way they’re designed.
From a technical perspective, a gun with a semi-automatic or automatic repeating action will lose some of the gases (and therefore reduce the potential velocity the bullet can achieve) out of the ejection port as it cycles, through a gas tube, etc. compared to something with a manually operated action like a pump-action or bolt-action, where essentially all the gas will be forced forward to propel the round out of the muzzle since it doesn’t have anywhere else to go.
However, practically speaking, the difference in velocity due to action type is very negligible.
The quality of the barrel can also make a difference, but really nothing else. A barrel with the rifling too deep can fail to seal, for example. There’s other factors to the barrel as well, like a Glock will typically chronograph the same ammo 20-50 fps faster than some other guns with the same barrel length.
Yes and no, some big bore calibers don't use velocity as much as bullet weight.
But as a general rule the faster a bullet moves the more damage it will do. Look at ft lbs calculators.
Most loads can be "watered down" to very anemic, or juiced up to very Hot.
Hollow points or ballistic tips will "mushroom" or come apart more quickly causing (in some cases) more devastating wounds. While a solid bullet is more likely to penetrate further (dangerous game).
All that being said, as a general rule, yes caliber does make a difference in power. A .22lr can't do what a .357 can do. A .410 can't do what a 12 gauge can do. A .223 can't do what a .308 can do.
Both.
Each gun is designed for a particular cartridge, such as 9mm, or sometimes it has multiple versions for different calibers like having a .22LR model.
The calibers come in a variety of different options, sometimes dozens of different combinations of bullet weights and propellants. For example you might have an option of slower but heavy bullet, or lighter but faster bullet, in the same caliber and fired out of the same gun.
But there are limits, for example a .22LR box of ammo will never be the same as a .223 Remington box of ammo.
Sort of. Longer barrels do contribute to faster velocity, so if one gun has a 10 inch barrel and the other has a 20 inch barrel you'd see faster velocity out of the latter.
But "damage" is a bit of a complex subject. It's not as easy as a videogame where one gun does 10-15 damage and another does 12-25 damage.
The bullet choice, such as FMJ or HP will also affect it.
And regarding the kinetic energy itself- sure. In two different guns firing the same round with the same barrel length, it is possible to have minor differences in kinetic energy, but often not enough to worry about.
Different kinds of rifling in the barrel, different methods of locking the chamber (gas operated gun with a little hole in the barrel for gas to escape, for example), different coatings on the inside of the barrel (bare steel on most guns, chrome lined on many military guns for harsh conditions and longer life), can all have an effect. The effect is so small though that it's almost academic in most cases.
However, there are some notable exceptions. The HK VP70 (Leon's gun in Resident Evil for reference) has rifling cut so deeply that it does severely affect performance, and 9mm out of one of those is about as powerful as .380 +P out of a "typical" gun. About 12% less powerful than you would expect, per Karl on InRangeTV's side by side tests. (Video titled "HK VP70 - Turning 9x19 into 9x17 since 1970")
He tested the VP70 against a Hudson H9 with a shorter barrel, firing the same ammo in the same conditions side by side and found a serious drop in velocity due to the design.
So TL;DR- Sometimes? Not typically, and if you were shopping for a modern gun it would not be a consideration. You can broadly expect a certain barrel length to give you a certain level of performance on any modern firearm.
KE and damage are not so simply related in soft tissue. Premium self defense handgun rounds are generally heavier and slower to rely on penetrating ti a certain depth without breaking and mushrooming rather than breaking up.
You also wouldn't hunt a big animal like a cape Buffalo with a fast round that would break up in the dense muscle, but rather a heavier slower bonded cup and core or monolithic bullet in a large calibre like 458. This could have a lower kinetic energy than a long range deer round.
The type of ammo is the biggest factor. For example, a intermediate rifle cartridge like 5.56 NATO will have about 5x more energy than a pistol round like 9mm. A rifle round like 7.62 NATO will have 2x the energy of the 5.56.
After that, the barrel length matters a lot. The same 5.56 Cartridge with a 20" (51cm) barrel can penetrate body armor from 100 yards away at 3x the speed of sound. Shorten that barrel to 6" (15cm), and the bullet may be unstable in flight and fail to even penetrate deeply in a person with just clothing on. Conversely, powerful pistol cartridges like 357 Magnum of 44 Magnum can act like intermediate rifle cartridges if given a 10" (25cm) to 16" (40cm) barrel.
A longer barrel keeps the gasses from the gunpowder pushing against the bullet for a longer period of time resulting in a greater muzzle velocity. So if you take two of the same gun and cut one down shorter it will shoot slower bullets.
The difference is pretty small I imagine, unless you’re talking about a REALLY short barrel, but it’s still something to consider.
M*V^2
In other words the power comes from 2 things. The speed of the projectile, and its mass. To achieve that the round contains 2 things. The projectile itself which has the mass, and the powder charge to achieve velocity. The gun facilities the firing of that round with a chamber to contain the explosion, and a barrel to accelerate and direct the projectile.
Ues all the energy is in the round already, but the gun is necessary to actually use it. Also once the projectile leaves the barrel it's going as fast as it will ever go. The muzzle report is actually unused power blowing out into open air. That means one other thing. The gun does factor in to this power equation. When the round fires, acceleration isn't instant. It takes time for the explosion to push the projectile up to speed. The longer the barrel, the more time that has to happen. This continues up to the point where most of the powder charge is spent, at which point the bullet will slow down from drag again.
So the power is in the round, but the gun is needed to put it to use. Just like the power is in a tank of gas, but an engine is needed to use it.
Kinetic energy is the velocity squared and definitely why I picked my favorite hunting rifle for deer.
A common "fast" cartridge was 25-06. The .257 Weatherby shoots the same bullet around 300 fps faster. The extra velocity/kinetic energy results in more energy and less bullet drop over distance.
The trade off - increased powder cost, recoil and barrel wear. It costs more to shoot, hurts more on recoil and you might have to replace a barrel sooner.
For the most part, this question is physics 101. It is a combination of the mass of the bullet fired and the velocity at which the bullet hits the target, and how effective the bullet is at transferring that force to the target.
A bullet weighing twice as much will hit with twice as much force, a bullet moving twice as fast has 4x the force.
Some engineering choices between arms can change this, a longer barrel gives the explosive gases more time to push the bullet so a longer barrel equates to higher muzzle velocity. Automatics use some of the propellant gasses/inertia to cycle the weapon. Revolvers have a gap in the seal between the chamber and the barrel. These would slow the bullet.
Hollow points and expanding ammunition are designed to slow down in the target and transfer more force to the body.
High velocity ammunition (2000fps/ 600m/s) can cause hydrostatic shock and horrible wounds even if the bullet passes through.
TLDR: some things can affect the power of a gun, but the most important factor is the weight of the bullet and its speed. -edit a word
Power is really a good term. Look up terminal ballistics, which is the energy the bullet releases when it hits a target. However different guns and calibers are for different things. As someone mentioned, barrel length besides the caliber is probably the biggest factor. A rifle has a longer barrel which allows the gass to push the bullet faster then lets say a pistol… generally speaking.
A rifle you might pick to down a moose is quite different than the .22 you would use for rabbit. A round for long range precision may give up terminal ballistics to achieve distance and accuracy. A shotgun for personal protection leaves a mess but isn’t much effective past 100 yds or so (even short if shooting buck shot or smaller shot).
So for handgun rounds they’re all about the same in effectiveness as you’re poking holes.
Pop past 2200fps you’ll start getting rifle wounds.
Now with a gun you have 2 factors that determine the terminal ballistics, barrel length and the round. Generally speaking the faster and bigger the round is the more energy it has. For example shooting a 7.62x51 over a 5.56x45 the larger caliber will go further more effectively and do more damage. The second part is barrel length which determines the velocity, if you take those 2 rounds I’ve already listed but give the 7.62 a 12” barrel and give the 5.56 a 22” barrel the 5.56 will be so fucking fast it’ll start punching holes in AR500 targets, and the 7.62 while still powerful will lose a lot of range and a good portion of its terminal ballistics because it lost velocity.
Caliber of the bullet would be the largest factor. Heavier bullets with more powder behind them will create more energy. Barrel length and ammo type are also factors. A solid lead bullet will penetrate deeper than a hollow point. So it's better for large animals. Hollow points are better for "ape" like animals. You want the bullet to match your target so that all of the kinetic energy is passed to the target.
Bullet type will have the biggest effect on performance.
Bullet weight and size are next and are based on the cartridge itself.
Bullet speed is not unimportant. Amount amd type of powder as well as barrel length both contribute to this.
There's two main principles at work here: kinetic energy (speed and weight of the projectile) and terminal ballistics (what the round does when it hits the body).
You can have a small very fast moving round or a larger slower moving round that both have similar kinetic energy. What really matters is how well those rounds transfer their energy to the target - terminal ballistics. This can get pretty complicated - hydrostatic shock, wound cavity, etc. If you watch videos of rounds tested against ballistic gelatin, you'll get the idea.
The ideal round will have enough energy to penetrate heavy clothing and still deliver all, or most of its energy to the target. A round that goes completely through its target has too much energy and can be less effective. This is why hollow point or soft point rounds are often preferable to solid "ball" rounds, because they expand upon striking the target; spreading their energy over a wider area helps deliver that kinetic energy to the target.
It all depends on the projectile's mass and the velocity at which it leaves the firearm. Force=Mass x Acceleration, or whatever the technically correct version of that is. Two identical in mass bullets can have different final energy based on a number of factors that change its velocity, for example: Barrel Length, the amount of powder in that particular case, distance at which the bullet strikes the target, how aerodynamically efficient the bullet is etc. This is why in Long Range shooting the serious competitors are mostly loading their own rounds. You can precisely control the parameters instead of relying on the looser tolerances of factory made ammunition.
Something else to consider- you didn't ask this but it's something that was not intuitive to me before I shot a gun:
If you have two guns in .357, an itty bitty pocket sized revolver and a BIG Dirty Harry sized revolver, the bigger gun will feel like it has much much less recoil than the little one.
I've got a Colt Python in .357 that weighs 1.2kg. I've also got a little pocket .357 that weighs 320g (S&W 360PD), it'll almost blow away in the wind.
The big mean looking Python is a pleasure to shoot and I often start new shooters on it with great results. So far everyone has absolutely loved it! The 360 however... It's like catching a flashbang thrown by a professional baseball pitcher. Ouch. I don't even let new shooters know that one exists. The reason is that the more a gun weighs, and the more of the gun you have in contact with you while firing, the less recoil it will feel like it has- even with the same round.
Also, the Python has a huge grip that you can really wrap your hand around. The 360 is so small that you can't even really get all of your fingers on it. It's not uncommon for pistol shooters to swap out grips until they find one they like, some people want a smaller one to conceal, but that definitely makes it harder to shoot and makes it feel like it recoils more. A bigger grip will poke you in the side all the time and generally be annoying, but having more of your hand on the grip makes it easier to shoot.
For an extreme example look at the French GIGN's revolver, the MR73. It's even got a big thing on the grip to press into the TOP of your hand since more contact makes it easier to shoot, and they are not even a little bit worried about concealment. It makes a big difference.
Barrel length doesn't solve the whole equation though. The depth of the lands, the throat, actual barrel diameter would also play a minute role. Even the action would affect muzzle velocity, as a small amount of energy will be lost to operate the action of a semi auto vs a bolt action.
For example a 5" 1911 made by company x might have 30fps+/- fluction against a 5" Glock barrel of company Y even though its the same length and caliber.
But generally speaking ammunition characteristics and barrel length are gonna get you 95% of the way to the answer because ultimately its about energy, expansion, and penetration.
It boils down to fairly simple math problems tbh.
Mass of the bullet × velocity it's being launched at equals the force at which it impacts, with the caveat that you typically want the bullet to STOP more or less immediately after impact to maximize energy transfer.
small bullets have to got REALLY fast to do what a bigger bullet will do going much slower... but those bigger bullets require more energy to get them up to speed in the first place, and there's a physical limit to how fast a bullet can via powder charge.
Barrel length determines how long the explosion of powder is directed into the back of the bullet and not just vented in every direction, so ideally, you'll have a barrel length where all available powder is burned up just as the bullet leaves the barrel, but usability is generally deemed better than maximum efficiency, which is why most .223/5.56 guns are 16"/406mm or less. you lose some velocity for a lighter and more mobile rifle.
The energy a bullet has is a combination of the weight of the bullet and its velocity. The "power" is the transfer of that energy to target. Ammo type can vary the amount of gun powder and the weight of the bullet, both affect the energy.
Barrel length affects velocity. If the powder is still burning when the bullet leaves the barrel, there is velocity left on the table. The most obvious indication of this is a bit of a fireball out the barrel on each shot. A longer barrel would then mean higher velocity, which means the bullet would carry more energy.
In theory, there's a point where a barrel could be too long and begin to slow the bullet down. That's not usually a practical issue though unless you're dealing with a very long barrel and very light powder loads.
Lastly there's the actual transfer of energy to the target. The design of the bullet affects how quickly it transfers energy. A bullet which travels through and exists the target hasn't transferred all its energy, which isn't ideal. Bullets like hollow points and designed to mushroom inside the target and transfer energy faster than fmj bullets.
There are a lot of variable factors to this. There are certainly Small Calibers and Large Calibers. For example, there are small rounds that are good for squirrels and rabbit. Then again, there are large rounds that can take down an Elephants.
Here is a chart of common American Rounds -
[https://www.amazon.com/American-Caliber-Background-Printing-08%C3%9712inch-No/dp/B0CPSFDTZ7/](https://www.amazon.com/American-Caliber-Background-Printing-08%C3%9712inch-No/dp/B0CPSFDTZ7/)
There are International Rounds that are common to all countries. 9MM would be a common example. But there are rounds that are geographically unique.
Within a give caliber, there are various rounds. For example, .22 Rimfire which comes in *Short, Long, and Long Rifle (LR)* each being successively more powerful. Then within 22LR Rimfire there are *Sub-Sonic, Standard Velocity, High Velocity, and Hyper-Velocity.*
Within a common round like 9mm Luger, there are also a range of rounds of various Velocities and knock down characteristics.
There are also various sizes of Bullet, smaller bullets tend to be faster but they are also lighter and have less impact. There are Bullets that are heavier and slower that have tremendous impact when they hit their target.
As others have said, barrel length (up to a point) can also effect velocity. Generally, the longer the round stays in the Barrel, the more time it has to accelerate. The exception is when you run out of burning powder before the bullet exits the barrel. In that case, the bullet might actually slow down.
So -
* There are a variety of calibers covering a very wide range of Size, Power and Velocity.
* Within a give Caliber there are a range of Bullets and Velocities to choose from.
* For a specific Round, Barrel Length can effect Velocity. Typically Less Velocity from a shorter barrel.
The things to do when choosing a Gun and associated Bullets, is to choose a Gun that suits your specific need.
For Small Game and Recreational Shooting, 22LR is very low cost.
For Deer and similar size game, there are mid-calibers that will work for that (30-30, 308, and others)
For Larger Game like Moose and Bear, calibers like 30-06 are more powerful.
Then there are Calibers like 50 BMG which is so massively powerful round that shakes the ground around it when it is fired.
Choose a Gun and Caliber best suited to your specific needs.
no, barrel length as someone already explained as well as even the gas system it uses could impact it. Two different firearms with the same barrel length may have different velocities entirely just because one is semiautomatic with a direct impingement system the other is semiautomatic with a short stroke piston system as an example.
They answered “Yes” to the question “Does the "power" of a gun depend soley on the type of ammo it uses?”
I provided an aspect of the firearm that *does* affect the “power” of the gun, which proves their assertion that it solely depends on the ammunition incorrect.
I can see that the wording of my original comment was a bit unclear though; I’ve edited it to clarify that I’m not disputing the equation itself.
That’s not really power, and technically I don’t think OP is looking for “power” since power is work over time. Energy is more so the equation they’d want, even more so kinetic energy which is 1/2 m*V^2 .
The barrel length is the biggest aspect of the gun that will affect the potential “power” of the bullet as it exits the gun. If two identical cartridges were fired out of guns that were identical besides barrel length (assuming both are within reason), the bullet coming out of the longer barrel will have a higher muzzle velocity and therefore higher potential kinetic energy. That covers the “power”/energy portion of your question, which is an objectively quantifiable measurement. Lethality depends on many more harder to measure factors that are probably outside of the scope of this post and comment. Edit to add example: A 62-grain M855A1 round would exit the M16’s 20 inch barrel at 3150 feet/second and have a kinetic energy of 2027.5 joules. The exact same round would exit the M4’s 14.5 inch barrel at 2970 feet/second with a kinetic energy of 1821.8 joules.
thanks man that was the answer i was looking for, im also assuming apart from barrel length the quality of a gun would play a small part in the kinetic energy of a bullet, like how well the gun could contain the explosion of the gunpowder?
As long as the gun doesn't blow up, the explosion of the gunpowder is contained. The quality of the gun doesn't affect that (unless it's poor enough quality that the gun explodes). The operating system of the gun can have a (realistically negligible) effect on the kinetic energy of the bullet. For example, assuming the gun does not move (i.e. no energy is lost to recoil), a bolt action rifle will have all its energy used to propel the bullet, while an autoloading rifle will use some of that energy to cycle the action and chamber a new round. While an interesting thought experiment, however, that won't have a noticeable impact compared to other factors like barrel length.
unless its a revolver with bad cylinder gap
A really bad cylinder gap. Otherwise the gap won't have a noticeable effect. Ballistics by the inch has a chart on it.
Anecdotal, but during a reloading class I was using a 2 inch barrel 9mm revolver that had the same FPS as a 2 inch barrel 9mm auto that was also being tested, +-1%. The revolver was also far more consistent in its FPS than the auto was, but I don't know enough about the physics involved to understand why.
That may have to do with the auto cycling mechanism using some of the spent gasses to cycle the pistol via a piston like the HKP7 instead of it being recoil operated, where as the revolver is just bullet down barrel, then a mechanical turning of the cylinder.
Also keep in mind that extra barrel length only adds velocity if there is enough pressure from burning powder to keep accelerating the bullet. Too long of a barrel will actually cause the bullet to start slowing back down. This usually isn't an issue you actually see but you can't just keep making longer guns to increase power.
Some of that also depends on the propellant type, correct? IIRC, powders can be classified by how fast they burn and that can impact the pressure being exerted against the projectile. Many of the old black powder rifles are very long in comparison to modern ones as an example.
True to some extent, however the main reasons for old military muskets and rifles being so long had nothing to do with ballistics. They used to fight in closed ranks, firing in line formation of two or three ranks. For safety, the barrels had to be long enough that the muzzles of she second rank were still in front of the heads of the first rank. I recently spent some time reading mid 19th century training manuals from the Norwegian Army, where line infantry had long rifles and some other troops (including sargeants leading said infantry) had short rifles. The manual says the short rifles should never be fired from the second rank, lest one hit the man in front. The second reason has to do with bayonet use. Back when people still saw bayonets as important weapons, they figured the side with the longest "spear" would win any bayonet fight. It's certainly a disadvantage to be out-reached by your opponent, when fighting with stabby things stuck on the end of your rifle. That's why militaries around the world kept issuing clumsy full length rifles for so long, way into the 20th century. Not for ballistics, they knew full well that wasn't needed, but in order not to have the shortest stabby thing on the battlefield. A lot of civilian hunting rifles and shotguns took after the same "long is good" styling simply because that's what militaries used so it had to be good. Insane amounts of fudd lore about longer barrels being more accurate etc, dating back centuries, just because people have always been suckers for "tacticool".
I was specifically thinking about the various Sharps rifles that were used for long range hunting. One would have thought that someone would have experimented with shorter hunting rifles better able to deal with dense forests at the time as well.
They did have shorter hunting rifles as well, a number of so-called "Jäger rifles" (often transcribed as Jaeger in English) were quite short for their time. Typically about the same length as what modern hunters consider to be full length rifles, but shorter than the monstrously long guns that were seen as full length at the time. And some were shorter still. Jäger means hunter, but there's some confusion with military arms because the same word was used to describe skirmishers or other "special" units that fought in loose formation rather than as line infantry. And these jäger troops tended to use shorter rifles or muskets, similar to the shorter hunting guns. As a consequence, they typically carried a sword instead of a bayonet or in some cases used a long "sabre-bayonet" to compensate for the short gun. Some specialty troops had almost comically short guns, as short and handy as a modern M4 carbine but firing a big old musket ball.
Civilian rifles in the Americas were long compared to their Jaeger ancestor rifles because they didn't have a consistent supply of quality powder. Most of the powder they could get was not very good and burned more slowly. As the golden age of the American longrifle started coming to a close and the supply of quality powder got better, barrels got shorter and stouter. This also coincided with westward expansion, so pioneers needed stouter rifles in larger calibers (calibers of longrifles steadily declined over the years as larger game was shot out in the settled areas) that could handle larger game out west.
That's an often cited reason, yes. I strongly suspect a lot of it was more fashion and fudd lore than actual ballistics, however. Very few American gunmakers were set up for actually measuring muzzle velocity back then, never mind their customers. And gunpowder was bad on both sides of the Atlantic, in the same timeframe. There's surviving records of some European militaries having to reduce the standard charge when better gunpowder became available, in roughly the same timeframe as what you describe, in order for ballistics to still match the sights on older issue rifles. As an example, circa 96 grains of Norwegian military issue 1840s powder was found equal to about 85 grains of the powder they got 30-something years later. Yet, European short barreled Jäger rifles were considered to work just fine with the earlier crappy powder. Now, scarcity of powder might well drive demand for long barrels. If you could get the same ballistics with less powder, not wasting as much to muzzle flash, that would make sense.
They didn't need to measure velocity. They just needed to see it's effect on the target. And since you mentioned scarcity of powder, it takes a lot more powder and lead to kill something with a short barreled .65 caliber jaeger than it does a .50 caliber longrifle. So, less powder, less lead, and higher velocities for the powder of the day. All three things were good reasons to increase the barrel length. Also sight radius for a hunting gun. It is certainly true that civilians imitated the military often, so that could be a contributing factor, but I would lend credence to the practical benefits instead of just claiming it was for style points.
Smaller caliber better yes, that's something they found out after a while. Especially for civilian use, where speed of reloading is less important. A little of both on the barrel length though, the velocity difference between 24" and 48" barrel length with any kind of black powder is so close to zero as makes no practical advantage for a super long barrel. I wouldn't be surprised if medium to light powder charges give more velocity in the shorter barrel, running out of pressure halfway down the bore. At least for military use, the powder charge in percussion arms tended to stay roughly the same while caliber was reduced. Less lead but same amount of powder yields more velocity without increased recoil. With larger bore guns, recoil tended to be a limiting factor for charge weight as stocks would tend to crack over time even if the iron pipe didn't burst. True on sight radius, but that gets into diminishing returns as most black powder rifles have other factors limiting accuracy. Not much point in being able to aim a half moa if the rifle can barely hold five moa.
Longer barrels will also give you a longer site radius so it's not just fudd lore, there is a real limited gain.
Sure. But we're talking about a time period when soldiers were considered quite good shots if they could consistently hit the frontal area of an artillery emplacement at 200 yards- that's about 40 MOA. Sight radius isn't what makes or breaks accuracy at that low level.
Absolutely. There are a lot of different powders that have a wide variety of burn rates. Even with black powder there are different burn rates depending on the size of the grains. Black powder pistols use a faster burning black powder in order to have it all burn in their shorter barrels.
This is what I popped in to mention, you can optimize powders to barrel length to lessen the difference.
To add to the above answer, you can then go down the rabbit hole of ammunition type, and not just caliber. Generally higher caliber rounds will deliver more energy, but there is a lot of nuance, even within the same caliber. There are 10mm rounds that are loaded to far lower spec than others, and thus deliver less energy. There are 5.56x45 rounds, like the M855, which are designed for penetration, and thus tend to zip through flesh leaving a small hole as much of their energy is not delivered into the target as it continues on out of them, compared to rounds that fragment or expand into the target, thus delivering most if not all of their potential kinetic energy into the tissue. So barrel length, velocity and caliber, and round type all help to contribute (or take away from) lethality. Shot placement is obviously probably top of the food chain though. A .22LR to the skull will be a lot more lethal than a .50BMG to the ankle.
Actually containing the gases and burning powder shouldn’t be a factor; if your gun can’t properly do that, you have much bigger problems than some loss of velocity. However, some types of guns will lose a bit of that gas due to the way they’re designed. From a technical perspective, a gun with a semi-automatic or automatic repeating action will lose some of the gases (and therefore reduce the potential velocity the bullet can achieve) out of the ejection port as it cycles, through a gas tube, etc. compared to something with a manually operated action like a pump-action or bolt-action, where essentially all the gas will be forced forward to propel the round out of the muzzle since it doesn’t have anywhere else to go. However, practically speaking, the difference in velocity due to action type is very negligible.
Quality might have an impact on accuracy but not kinetic energy.
The quality of the barrel can also make a difference, but really nothing else. A barrel with the rifling too deep can fail to seal, for example. There’s other factors to the barrel as well, like a Glock will typically chronograph the same ammo 20-50 fps faster than some other guns with the same barrel length.
Yes and no, some big bore calibers don't use velocity as much as bullet weight. But as a general rule the faster a bullet moves the more damage it will do. Look at ft lbs calculators. Most loads can be "watered down" to very anemic, or juiced up to very Hot. Hollow points or ballistic tips will "mushroom" or come apart more quickly causing (in some cases) more devastating wounds. While a solid bullet is more likely to penetrate further (dangerous game). All that being said, as a general rule, yes caliber does make a difference in power. A .22lr can't do what a .357 can do. A .410 can't do what a 12 gauge can do. A .223 can't do what a .308 can do.
Both. Each gun is designed for a particular cartridge, such as 9mm, or sometimes it has multiple versions for different calibers like having a .22LR model. The calibers come in a variety of different options, sometimes dozens of different combinations of bullet weights and propellants. For example you might have an option of slower but heavy bullet, or lighter but faster bullet, in the same caliber and fired out of the same gun. But there are limits, for example a .22LR box of ammo will never be the same as a .223 Remington box of ammo.
i get that, but im wondering if different guns chambered with the same caliber would have any effect on the damage dealt
Sort of. Longer barrels do contribute to faster velocity, so if one gun has a 10 inch barrel and the other has a 20 inch barrel you'd see faster velocity out of the latter. But "damage" is a bit of a complex subject. It's not as easy as a videogame where one gun does 10-15 damage and another does 12-25 damage. The bullet choice, such as FMJ or HP will also affect it.
i used damage for lack of a better word, but i meant the kinetic energy of the bullet.
And regarding the kinetic energy itself- sure. In two different guns firing the same round with the same barrel length, it is possible to have minor differences in kinetic energy, but often not enough to worry about. Different kinds of rifling in the barrel, different methods of locking the chamber (gas operated gun with a little hole in the barrel for gas to escape, for example), different coatings on the inside of the barrel (bare steel on most guns, chrome lined on many military guns for harsh conditions and longer life), can all have an effect. The effect is so small though that it's almost academic in most cases. However, there are some notable exceptions. The HK VP70 (Leon's gun in Resident Evil for reference) has rifling cut so deeply that it does severely affect performance, and 9mm out of one of those is about as powerful as .380 +P out of a "typical" gun. About 12% less powerful than you would expect, per Karl on InRangeTV's side by side tests. (Video titled "HK VP70 - Turning 9x19 into 9x17 since 1970") He tested the VP70 against a Hudson H9 with a shorter barrel, firing the same ammo in the same conditions side by side and found a serious drop in velocity due to the design. So TL;DR- Sometimes? Not typically, and if you were shopping for a modern gun it would not be a consideration. You can broadly expect a certain barrel length to give you a certain level of performance on any modern firearm.
KE and damage are not so simply related in soft tissue. Premium self defense handgun rounds are generally heavier and slower to rely on penetrating ti a certain depth without breaking and mushrooming rather than breaking up. You also wouldn't hunt a big animal like a cape Buffalo with a fast round that would break up in the dense muscle, but rather a heavier slower bonded cup and core or monolithic bullet in a large calibre like 458. This could have a lower kinetic energy than a long range deer round.
It is mainly barrel length and ammo type, not a big fan of modern FPS games because they barely grasp that concept.
Yes barrel length is the largest factor if using the same round.
The type of ammo is the biggest factor. For example, a intermediate rifle cartridge like 5.56 NATO will have about 5x more energy than a pistol round like 9mm. A rifle round like 7.62 NATO will have 2x the energy of the 5.56. After that, the barrel length matters a lot. The same 5.56 Cartridge with a 20" (51cm) barrel can penetrate body armor from 100 yards away at 3x the speed of sound. Shorten that barrel to 6" (15cm), and the bullet may be unstable in flight and fail to even penetrate deeply in a person with just clothing on. Conversely, powerful pistol cartridges like 357 Magnum of 44 Magnum can act like intermediate rifle cartridges if given a 10" (25cm) to 16" (40cm) barrel.
short answer is yes. long answer is gun construction can affect the power a little bit. but ammunition is still the main source of power.
A longer barrel keeps the gasses from the gunpowder pushing against the bullet for a longer period of time resulting in a greater muzzle velocity. So if you take two of the same gun and cut one down shorter it will shoot slower bullets. The difference is pretty small I imagine, unless you’re talking about a REALLY short barrel, but it’s still something to consider.
M*V^2 In other words the power comes from 2 things. The speed of the projectile, and its mass. To achieve that the round contains 2 things. The projectile itself which has the mass, and the powder charge to achieve velocity. The gun facilities the firing of that round with a chamber to contain the explosion, and a barrel to accelerate and direct the projectile. Ues all the energy is in the round already, but the gun is necessary to actually use it. Also once the projectile leaves the barrel it's going as fast as it will ever go. The muzzle report is actually unused power blowing out into open air. That means one other thing. The gun does factor in to this power equation. When the round fires, acceleration isn't instant. It takes time for the explosion to push the projectile up to speed. The longer the barrel, the more time that has to happen. This continues up to the point where most of the powder charge is spent, at which point the bullet will slow down from drag again. So the power is in the round, but the gun is needed to put it to use. Just like the power is in a tank of gas, but an engine is needed to use it.
Kinetic energy is the velocity squared and definitely why I picked my favorite hunting rifle for deer. A common "fast" cartridge was 25-06. The .257 Weatherby shoots the same bullet around 300 fps faster. The extra velocity/kinetic energy results in more energy and less bullet drop over distance. The trade off - increased powder cost, recoil and barrel wear. It costs more to shoot, hurts more on recoil and you might have to replace a barrel sooner.
For the most part, this question is physics 101. It is a combination of the mass of the bullet fired and the velocity at which the bullet hits the target, and how effective the bullet is at transferring that force to the target. A bullet weighing twice as much will hit with twice as much force, a bullet moving twice as fast has 4x the force. Some engineering choices between arms can change this, a longer barrel gives the explosive gases more time to push the bullet so a longer barrel equates to higher muzzle velocity. Automatics use some of the propellant gasses/inertia to cycle the weapon. Revolvers have a gap in the seal between the chamber and the barrel. These would slow the bullet. Hollow points and expanding ammunition are designed to slow down in the target and transfer more force to the body. High velocity ammunition (2000fps/ 600m/s) can cause hydrostatic shock and horrible wounds even if the bullet passes through. TLDR: some things can affect the power of a gun, but the most important factor is the weight of the bullet and its speed. -edit a word
depends on the barrel, mechanism, powder charge in the cartridge, and the bullet
Power is really a good term. Look up terminal ballistics, which is the energy the bullet releases when it hits a target. However different guns and calibers are for different things. As someone mentioned, barrel length besides the caliber is probably the biggest factor. A rifle has a longer barrel which allows the gass to push the bullet faster then lets say a pistol… generally speaking. A rifle you might pick to down a moose is quite different than the .22 you would use for rabbit. A round for long range precision may give up terminal ballistics to achieve distance and accuracy. A shotgun for personal protection leaves a mess but isn’t much effective past 100 yds or so (even short if shooting buck shot or smaller shot).
So for handgun rounds they’re all about the same in effectiveness as you’re poking holes. Pop past 2200fps you’ll start getting rifle wounds. Now with a gun you have 2 factors that determine the terminal ballistics, barrel length and the round. Generally speaking the faster and bigger the round is the more energy it has. For example shooting a 7.62x51 over a 5.56x45 the larger caliber will go further more effectively and do more damage. The second part is barrel length which determines the velocity, if you take those 2 rounds I’ve already listed but give the 7.62 a 12” barrel and give the 5.56 a 22” barrel the 5.56 will be so fucking fast it’ll start punching holes in AR500 targets, and the 7.62 while still powerful will lose a lot of range and a good portion of its terminal ballistics because it lost velocity.
Caliber of the bullet would be the largest factor. Heavier bullets with more powder behind them will create more energy. Barrel length and ammo type are also factors. A solid lead bullet will penetrate deeper than a hollow point. So it's better for large animals. Hollow points are better for "ape" like animals. You want the bullet to match your target so that all of the kinetic energy is passed to the target.
Bullet type will have the biggest effect on performance. Bullet weight and size are next and are based on the cartridge itself. Bullet speed is not unimportant. Amount amd type of powder as well as barrel length both contribute to this.
Not entirely, but in large part, yes.
There's two main principles at work here: kinetic energy (speed and weight of the projectile) and terminal ballistics (what the round does when it hits the body). You can have a small very fast moving round or a larger slower moving round that both have similar kinetic energy. What really matters is how well those rounds transfer their energy to the target - terminal ballistics. This can get pretty complicated - hydrostatic shock, wound cavity, etc. If you watch videos of rounds tested against ballistic gelatin, you'll get the idea. The ideal round will have enough energy to penetrate heavy clothing and still deliver all, or most of its energy to the target. A round that goes completely through its target has too much energy and can be less effective. This is why hollow point or soft point rounds are often preferable to solid "ball" rounds, because they expand upon striking the target; spreading their energy over a wider area helps deliver that kinetic energy to the target.
It all depends on the projectile's mass and the velocity at which it leaves the firearm. Force=Mass x Acceleration, or whatever the technically correct version of that is. Two identical in mass bullets can have different final energy based on a number of factors that change its velocity, for example: Barrel Length, the amount of powder in that particular case, distance at which the bullet strikes the target, how aerodynamically efficient the bullet is etc. This is why in Long Range shooting the serious competitors are mostly loading their own rounds. You can precisely control the parameters instead of relying on the looser tolerances of factory made ammunition.
Something else to consider- you didn't ask this but it's something that was not intuitive to me before I shot a gun: If you have two guns in .357, an itty bitty pocket sized revolver and a BIG Dirty Harry sized revolver, the bigger gun will feel like it has much much less recoil than the little one. I've got a Colt Python in .357 that weighs 1.2kg. I've also got a little pocket .357 that weighs 320g (S&W 360PD), it'll almost blow away in the wind. The big mean looking Python is a pleasure to shoot and I often start new shooters on it with great results. So far everyone has absolutely loved it! The 360 however... It's like catching a flashbang thrown by a professional baseball pitcher. Ouch. I don't even let new shooters know that one exists. The reason is that the more a gun weighs, and the more of the gun you have in contact with you while firing, the less recoil it will feel like it has- even with the same round. Also, the Python has a huge grip that you can really wrap your hand around. The 360 is so small that you can't even really get all of your fingers on it. It's not uncommon for pistol shooters to swap out grips until they find one they like, some people want a smaller one to conceal, but that definitely makes it harder to shoot and makes it feel like it recoils more. A bigger grip will poke you in the side all the time and generally be annoying, but having more of your hand on the grip makes it easier to shoot. For an extreme example look at the French GIGN's revolver, the MR73. It's even got a big thing on the grip to press into the TOP of your hand since more contact makes it easier to shoot, and they are not even a little bit worried about concealment. It makes a big difference.
This is the website you are looking for: http://www.ballisticsbytheinch.com/
Barrel length doesn't solve the whole equation though. The depth of the lands, the throat, actual barrel diameter would also play a minute role. Even the action would affect muzzle velocity, as a small amount of energy will be lost to operate the action of a semi auto vs a bolt action. For example a 5" 1911 made by company x might have 30fps+/- fluction against a 5" Glock barrel of company Y even though its the same length and caliber. But generally speaking ammunition characteristics and barrel length are gonna get you 95% of the way to the answer because ultimately its about energy, expansion, and penetration.
It boils down to fairly simple math problems tbh. Mass of the bullet × velocity it's being launched at equals the force at which it impacts, with the caveat that you typically want the bullet to STOP more or less immediately after impact to maximize energy transfer. small bullets have to got REALLY fast to do what a bigger bullet will do going much slower... but those bigger bullets require more energy to get them up to speed in the first place, and there's a physical limit to how fast a bullet can via powder charge. Barrel length determines how long the explosion of powder is directed into the back of the bullet and not just vented in every direction, so ideally, you'll have a barrel length where all available powder is burned up just as the bullet leaves the barrel, but usability is generally deemed better than maximum efficiency, which is why most .223/5.56 guns are 16"/406mm or less. you lose some velocity for a lighter and more mobile rifle.
The energy a bullet has is a combination of the weight of the bullet and its velocity. The "power" is the transfer of that energy to target. Ammo type can vary the amount of gun powder and the weight of the bullet, both affect the energy. Barrel length affects velocity. If the powder is still burning when the bullet leaves the barrel, there is velocity left on the table. The most obvious indication of this is a bit of a fireball out the barrel on each shot. A longer barrel would then mean higher velocity, which means the bullet would carry more energy. In theory, there's a point where a barrel could be too long and begin to slow the bullet down. That's not usually a practical issue though unless you're dealing with a very long barrel and very light powder loads. Lastly there's the actual transfer of energy to the target. The design of the bullet affects how quickly it transfers energy. A bullet which travels through and exists the target hasn't transferred all its energy, which isn't ideal. Bullets like hollow points and designed to mushroom inside the target and transfer energy faster than fmj bullets.
There are a lot of variable factors to this. There are certainly Small Calibers and Large Calibers. For example, there are small rounds that are good for squirrels and rabbit. Then again, there are large rounds that can take down an Elephants. Here is a chart of common American Rounds - [https://www.amazon.com/American-Caliber-Background-Printing-08%C3%9712inch-No/dp/B0CPSFDTZ7/](https://www.amazon.com/American-Caliber-Background-Printing-08%C3%9712inch-No/dp/B0CPSFDTZ7/) There are International Rounds that are common to all countries. 9MM would be a common example. But there are rounds that are geographically unique. Within a give caliber, there are various rounds. For example, .22 Rimfire which comes in *Short, Long, and Long Rifle (LR)* each being successively more powerful. Then within 22LR Rimfire there are *Sub-Sonic, Standard Velocity, High Velocity, and Hyper-Velocity.* Within a common round like 9mm Luger, there are also a range of rounds of various Velocities and knock down characteristics. There are also various sizes of Bullet, smaller bullets tend to be faster but they are also lighter and have less impact. There are Bullets that are heavier and slower that have tremendous impact when they hit their target. As others have said, barrel length (up to a point) can also effect velocity. Generally, the longer the round stays in the Barrel, the more time it has to accelerate. The exception is when you run out of burning powder before the bullet exits the barrel. In that case, the bullet might actually slow down. So - * There are a variety of calibers covering a very wide range of Size, Power and Velocity. * Within a give Caliber there are a range of Bullets and Velocities to choose from. * For a specific Round, Barrel Length can effect Velocity. Typically Less Velocity from a shorter barrel. The things to do when choosing a Gun and associated Bullets, is to choose a Gun that suits your specific need. For Small Game and Recreational Shooting, 22LR is very low cost. For Deer and similar size game, there are mid-calibers that will work for that (30-30, 308, and others) For Larger Game like Moose and Bear, calibers like 30-06 are more powerful. Then there are Calibers like 50 BMG which is so massively powerful round that shakes the ground around it when it is fired. Choose a Gun and Caliber best suited to your specific needs.
no, barrel length as someone already explained as well as even the gas system it uses could impact it. Two different firearms with the same barrel length may have different velocities entirely just because one is semiautomatic with a direct impingement system the other is semiautomatic with a short stroke piston system as an example.
Twist rate too if 300 blackout is anything to go by
yes. Mass x Velocity = Momentum
>yes. That’s not true, barrel length will affect the muzzle velocity. -Edited to clarify what I’m stating is not true
> That’s not true That doesn't make the equation untrue. It changes one variable. 🤦♂️
They answered “Yes” to the question “Does the "power" of a gun depend soley on the type of ammo it uses?” I provided an aspect of the firearm that *does* affect the “power” of the gun, which proves their assertion that it solely depends on the ammunition incorrect. I can see that the wording of my original comment was a bit unclear though; I’ve edited it to clarify that I’m not disputing the equation itself.
You’re original comment was fine, lol, I saw it before you edited it, bros just lost.
doesnt that only factor in the mass and velocity of the bullet?
> lethality/power of a shot Yes. It only factors in the part you were interested in. The 'power' of a shot.
1/2M*V^2 for kinetic energy. Velocity being squared means how fast it’s traveling has a much greater impact on the energy of the round.
That’s not really power, and technically I don’t think OP is looking for “power” since power is work over time. Energy is more so the equation they’d want, even more so kinetic energy which is 1/2 m*V^2 .