Firearm Muzzle Energy

[Tweedle]

Can anyone point me to a comprehensive web-based resource that lists the muzzle energies of a variety of firearm types? Many thanks.

[Rapier]

I know its not necessarily online but Jane's is ALWAYS a GREAT source for anything military (and even civillian). They very frequently show up in the bargain bin in the book stores. Everytime I see one I buy it. I can't tell you the number of times I've walked over to the bookshelf for a bit of Jane.

[gewing]

http://www.ammoguide.com/

for certain cartridges, with some interesting loadings...
http://www.corbon.com/?uid=12665&page=1634
check the different price lists, they have velocity/etc.



Best thing to do would be to check used book stores, look for either
"Cartridges of the world" (probably best, really) there are many editions, I like the ones prior to the most recent better in most ways.

or Janes Ammunition guide.

If you find Janes Infantry weapons, LET ME KNOW.

[Kevin Rose]

Can anyone point me to a comprehensive web-based resource that lists the muzzle energies of a variety of firearm types? Many thanks.

I'm not really sure why you want this, as muzzle energy is really poorly correlated to anything useful. For example, a good roundhouse has more energy than many bullets. A 2x4 can easily deliver more energy than a .38 special. But here is one that I found in a quick search.

http://www.powernet.net/~eich1/sp.html

Not sure how comprehensive, but it looks ok.

This data set is also the Marshall and Sanow "data" on stopping power, which is basically worthless bit twiddling at best and clearly deceitful at worst. If you are tempted to use the "Success" column look at these two articles as to why it's not reliable:

http://www.firearmstactical.com/mars...crepancies.htm
http://www.firearmstactical.com/afte.htm

[Captain Obvious]

I'm not really sure why you want this, as muzzle energy is really poorly correlated to anything useful. For example, a good roundhouse has more energy than many bullets. A 2x4 can easily deliver more energy than a .38 special. But here is one that I found in a quick search.

I was wondering how long it would be before someone brought this up. Slow-rolling bowling ball, anyone?

[Toadmaster]

I'm not really sure why you want this, as muzzle energy is really poorly correlated to anything useful. For example, a good roundhouse has more energy than many bullets. A 2x4 can easily deliver more energy than a .38 special.

Because it is a readily available measuring method to compare differant bullets and it is not convieniant for most people to go out and conduct live fire trials on living subjects. Since there is no real reliable way to measure bullet effectiveness its as good as any other. I think you know the bowling ball, 2x4 analogies are bogus anyway, like most things its how you use it.


Tweedle, I second the recomedation for cartridges of the world, but since you were looking for online, try looking up the websites for ammunition manufacturers, most include ballistic tables. Winchester, Federal, CCI, CorBon, Remington, Speer to name a few.

[RDU Neil]

I think you know the bowling ball, 2x4 analogies are bogus anyway, like most things its how you use it.

It would be interesting to see these analogies specifically stated... and then specifically debunked, in a well reasoned post. Everyone around here makes general "slow rolling bowling ball" comments, without actually explaining them. While I understand the basic physics behind the comments, I'd rather have it spelled out, than just assume I know what you mean by the comment.

[Toadmaster]

It would be interesting to see these analogies specifically stated... and then specifically debunked, in a well reasoned post. Everyone around here makes general "slow rolling bowling ball" comments, without actually explaining them. While I understand the basic physics behind the comments, I'd rather have it spelled out, than just assume I know what you mean by the comment.

OK, here goes, I don't have time to do any detailed math I am just giving the concept so please don't pick at the math errors (I'm not going to find the actual surface area for a bowling ball for example)

I don't recall the exact formula for determining muzzle energy off the top of my head but basically it is velocity squared x bullet weight (one of the reasons the large caliber crowd dislikes muzzle energy, it favors velocity over weight), so a heavy but slow moving object like a bowling ball (lets say 12 pounds) can develop quite a bit of energy when compared to a fast moving but light bullet ( typically 100-250 grains or 1/4-1/2 ounce). So it is true that a bowling ball can have more energy than a bullet, but where this falls apart is surface area and velocity, the bowling ball divides its energy over a large area (lets say 9" diameter) vs a bullet that puts its energy into a small area (1/2" dia or less), so lets give the bowling ball 900 ft/lbs (about the same energy as a .44 Magnum) divided by 9" equals 100 ft/lbs per inch, now lets compare it to a .50 bullet with 400 ft/lbs, the .50 cal has 800 ft/lbs per inch. This is why you will find a bullet like the 9mm Parabellum with 350 ft/lbs penetrates better than a "more powerful" .45 ACP with 400 ft/lbs, the 9mm concentrates the energy into a smaller point. Using a similar idea you can pick up a 10 pound bowling ball in your hand without breaking your skin, but if you put a 1 pound weight sitting on a pin onto your hand it would puncture your hand.

There is also the issue of velocity, an object must have a minimum velocity to break the skin (IIRC around 100 feet per second).


Now the people that make these 2x4, bowling ball statements are correct that muzzle energy does not directly relate to the effect on living tissue and because of this they often claim that muzzle energy is paper energy (and they are correct since it is a formula) usually this is right before they give their own better formula (which of course is also a paper figure). The only real way to test a bullets effectiveness is to go out and shoot things but like I mentioned this is not conveniant, but has been done, goats were used in one study, hunting, police shootings and military use in others (after action reports for police and military use), geletin is often used but you will also find geletin has its detractors (this is where the now out of favor theory of temporary cavity came from).

All of this is why I like muzzle energy (for a game), its not perfect but its easy to access and in my opinion as good as any other method out there. It gives some referance between differant cartridges, and is nearly always given when a new cartridrige is introduced.

This is not to say other formulas are not just as good or maybe better, but muzzle energy works fine for me and is pretty much an industry standard (I've never seen a cartridge manufacturer give the Taylor Knock Out or IPSC power level of a cartridge).

Hope this helps.

[Captain Obvious]

So it is true that a bowling ball can have more energy than a bullet, but where this falls apart is surface area and velocity, the bowling ball divides its energy over a large area (lets say 9" diameter) vs a bullet that puts its energy into a small area (1/2" dia or less)...

This same reason is why it's not a good idea to let your friend stab you while you're wearing a bullet-proof vest. A knife has less energy than a bullet, but it's concentrated in a MUCH smaller area.

[RDU Neil]

OK, here goes, I don't have time to do any detailed math I am just giving the concept so please don't pick at the math errors (I'm not going to find the actual surface area for a bowling ball for example)

I don't recall the exact formula for determining muzzle energy off the top of my head but basically it is velocity squared x bullet weight (one of the reasons the large caliber crowd dislikes muzzle energy, it favors velocity over weight), so a heavy but slow moving object like a bowling ball (lets say 12 pounds) can develop quite a bit of energy when compared to a fast moving but light bullet ( typically 100-250 grains or 1/4-1/2 ounce). So it is true that a bowling ball can have more energy than a bullet, but where this falls apart is surface area and velocity, the bowling ball divides its energy over a large area (lets say 9" diameter) vs a bullet that puts its energy into a small area (1/2" dia or less), so lets give the bowling ball 900 ft/lbs (about the same energy as a .44 Magnum) divided by 9" equals 100 ft/lbs per inch, now lets compare it to a .50 bullet with 400 ft/lbs, the .50 cal has 800 ft/lbs per inch. This is why you will find a bullet like the 9mm Parabellum with 350 ft/lbs penetrates better than a "more powerful" .45 ACP with 400 ft/lbs, the 9mm concentrates the energy into a smaller point. Using a similar idea you can pick up a 10 pound bowling ball in your hand without breaking your skin, but if you put a 1 pound weight sitting on a pin onto your hand it would puncture your hand.

There is also the issue of velocity, an object must have a minimum velocity to break the skin (IIRC around 100 feet per second).


Now the people that make these 2x4, bowling ball statements are correct that muzzle energy does not directly relate to the effect on living tissue and because of this they often claim that muzzle energy is paper energy (and they are correct since it is a formula) usually this is right before they give their own better formula (which of course is also a paper figure). The only real way to test a bullets effectiveness is to go out and shoot things but like I mentioned this is not conveniant, but has been done, goats were used in one study, hunting, police shootings and military use in others (after action reports for police and military use), geletin is often used but you will also find geletin has its detractors (this is where the now out of favor theory of temporary cavity came from).

All of this is why I like muzzle energy (for a game), its not perfect but its easy to access and in my opinion as good as any other method out there. It gives some referance between differant cartridges, and is nearly always given when a new cartridrige is introduced.

This is not to say other formulas are not just as good or maybe better, but muzzle energy works fine for me and is pretty much an industry standard (I've never seen a cartridge manufacturer give the Taylor Knock Out or IPSC power level of a cartridge).

Hope this helps.

Excellent description... just what I needed. It is the "surface area" issue that I understood, but had never seen clearly stated. Thanks much.

I can see where this breaks down... as no matter the calculation, it is not easy to determine what that "muzzle energy" actually does with the bullet. Help it penetrate? Increase the impact? Both? Either or?

Seems to me that what is required is some kind of multi-step measurement.

1. Determine muzzle velocity.
2. Determine surface area of impact point or round.
3. Determine density of round vs. density of target (for penetration)
4. Determine deformation/fragmentation common to the material of round. (affects both penetration and damage done)
5. Determine "critical" factor of target impact area. (Kidney or calf muscle, side panel or engine block)

All that needs to go in to factoring the "effectiveness" of any given round fired at any given time. Highly subject to initial conditions and all that.

Interesting stuff.

[Toadmaster]

Excellent description... just what I needed. It is the "surface area" issue that I understood, but had never seen clearly stated. Thanks much.

I can see where this breaks down... as no matter the calculation, it is not easy to determine what that "muzzle energy" actually does with the bullet. Help it penetrate? Increase the impact? Both? Either or?

Seems to me that what is required is some kind of multi-step measurement.

1. Determine muzzle velocity.
2. Determine surface area of impact point or round.
3. Determine density of round vs. density of target (for penetration)
4. Determine deformation/fragmentation common to the material of round. (affects both penetration and damage done)
5. Determine "critical" factor of target impact area. (Kidney or calf muscle, side panel or engine block)

All that needs to go in to factoring the "effectiveness" of any given round fired at any given time. Highly subject to initial conditions and all that.

Interesting stuff.

Which is one of the major reasons guns cause so much discussion, even organizations with nearly unlimited resources can't come up with concrete answers (FBI keeps changing weapons, .357 Mag, .38 Special, 9mm, 10mm, .40 S&W and now back to the "obsolete" .45, the US Military .30-06, 7.62mm 5.56mm, 6.8mm? and .45, 9mm and back to .45?) its not surprising that gamers and casual users argue. What is important? penetration in armor, the size of the hole left behind, what color the shooters socks are?

This is also why I think muzzle energy is Ok, there is no formula that will say "a gun with x,y,z will do x damage, but it seems fair to me to use such a formula (and IPSC power factor, Hatchers formula, Taylor Knock Out etc may be just as valid) to rate the cartridges relationship to each other. So if you determine a .45 with 430 ft/lbs of energy does 1d6+1, then it is safe to assume a .22 LR with 140 ft/lbs will do less damage and a .357 magnum with 540 ft/lbs may do a little more. Not perfect but it is just a game, if you are buying a gun for home defense then it probably deserves a little more research.

Certainly your audience plays into it as well, I happen to play with a bunch of gun nuts, we are obviously going to put a little more trouble into how guns work than say a gaming group in Sweden (just an example country) whose average player may not have even seen a real gun let alone shot one.

[Cpt.Storm]

Maybe this will help as well... I'm a college instructor and I teach physics and this question comes up all the time...

Newton's Third Law states, 'for every action there is an equal and opposite reaction.' Taking this into account, if the energy of a bullet were enough to knock over a person then firing the gun would also knock over the shooter.

Coupled with this, of course, is the mass of bullet compared to the mass of the target. Inertia, as understood by Newton's 2nd law is the tendency for an object that is stationary to stay stationary and one that is motion to continue in motion. Now, when two bodies collide their mass is taken into account. I think it's safe to say that a bullet is much less massive than a human body, hence no flying 10 feet backwards.

Finally, there is kinectic and potential energy. While the bullet is travelling it has kinetic energy. When it hits the body that kinetic energy is at its highest amount. If a bullet goes through and through, very little damage is done because the time of impulse (the amount of time the bullet is in contact with the body) is very short. This is why they make bullets that flatten upon impact. This causes the impulse time to go exponentially and also slows the bullet down so that it will bounce off bones rather than go through them. The longer the bullet is moving through the body, the more damage it does. Gruesome, yes, but effective.

I hope this helps.

[RDU Neil]

Maybe this will help as well... I'm a college instructor and I teach physics and this question comes up all the time...

Newton's Third Law states, 'for every action there is an equal and opposite reaction.' Taking this into account, if the energy of a bullet were enough to knock over a person then firing the gun would also knock over the shooter.

This isn't assuming balance and bracing against recoil, correct? I mean, I can throw a punch that takes someone off their feet, but my stance and momentum makes up for the fact that there is equal reaction, and I don't go flying in the other direction. Same for shooting, correct?

Finally, there is kinectic and potential energy. While the bullet is travelling it has kinetic energy. When it hits the body that kinetic energy is at its highest amount. If a bullet goes through and through, very little damage is done because the time of impulse (the amount of time the bullet is in contact with the body) is very short. This is why they make bullets that flatten upon impact. This causes the impulse time to go exponentially and also slows the bullet down so that it will bounce off bones rather than go through them. The longer the bullet is moving through the body, the more damage it does. Gruesome, yes, but effective.

Right... this is an issue I've never seen addressed by a game system very well. The fact that penetration can happen, be so complete, that little damage is actually done to the body, wall, whatever. I wonder if there is an easy system for allowing true "blow through" in Hero? You can always calculate body of attack vs. rDef and body of target, but this assume full release of energy into target, rather than over penetration and that energy continuing on to something else. It probably gets to complicated to have such a concept in an RPG, since it would depend on all those things I listed above, and essentially be a "case by case" basis for every round fired, and that's just not feasible for an RPG and still be "fun."

I hope this helps.

Yes... thanks.

[Toadmaster]

This isn't assuming balance and bracing against recoil, correct? I mean, I can throw a punch that takes someone off their feet, but my stance and momentum makes up for the fact that there is equal reaction, and I don't go flying in the other direction. Same for shooting, correct?

Much apparently also has to do with the targets reaction to being hit, you can throw a punch at a 150lb person and knock them to the ground but if you threw that same punch at a 150lb slab of beef it would barely move. The same goes for bullets, most of the "knockback" seen is the result of the body reacting to being hit, not the bullet knocking the target down (A bullet that weighs 1/2 ounce is pretty heavy, but it is still only 1/2880 the weight of a 90lb weakling).

As for blow through I've been reading GURPS 4e and I rather like their new blow through rule, a person only stops 10 pts of damage, the rest continues on able to possibly hit something else. The target still takes full damage it just doesn't soak up all of the bullets energy, of course body armor needs to be considered as well and they point out the bullet must penetrate the armor on the backside while exiting just like it did entering.

I don't see why this wouldn't work just fine for HERO although you may need to adjust for the lower damage of HERO, maybe only 5 or 6 Body not 10, so most pistols would have some danger of over penetration while powerful pistols (.44 Mag etc) and rifles have a pretty fair chance.

To provide an example say we have Ned Notsobright, he is in the midst of robbing the Bigger is not good enough gun shop, when the owner gets the drop on him with his .800 Cthulhu Express (TM) letting loose with all 4 barrels (we will just deal with one bullet though for simplicity), Ned has 10 body and Class 2 body armor (worth say 5 pts of armor), the .800 CE does 4d6 rolling a 19, Ned takes 14 body (19 minus the 5 pts of armor), but the .800 CE is only slowed by 15 (5 for the front of the vest, 5 for Ned and 5 for the back of the vest) 4 pts continue on to damage an unfortunately placed 3rd dynasty Ming Vase.

Shouldn't be to complicated and adds some variety to the game (know whats behind your target).

I think DC also had some mention of this option but that might be my imagination.

[Cpt.Storm]

This isn't assuming balance and bracing against recoil, correct? I mean, I can throw a punch that takes someone off their feet, but my stance and momentum makes up for the fact that there is equal reaction, and I don't go flying in the other direction. Same for shooting, correct?

Absolutely, though if you brace too well and have a very powerful weapon that is meant to recoil you will shatter your shoulder. OUCH!