# Gun Users: Muzzle energy from different guns--these numbers can't be right??
**URL:** https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700
**Category:** Factual Questions
**Created:** [February 29, 2004, 2:38am UTC](https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700 "2004-02-29T02:38:23Z")
**Posts on this page:** 18
**Page:** 1
### Author:  [@js\_africanus](https://boards.straightdope.com/u/js_africanus)
#### Post date: [February 29, 2004, 2:38am UTC](https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700/1 "2004-02-29T02:38:23Z")
I have a Glock 21. It is a .45. The manual tells me that I can expect the muzzle energy of this gun to be approximately 460 J. (That’s joules, right?) By way of comparison, their 10mm, a gun which I was told was too powerful for the FBI agents causing them to switch to a .40 cal., offers an approximate 750 J.
Now, I’m looking at a manual for a Taurus revolver. Specifically, the .357 magnum is listed as having a bullet weight of 158 grain (a typical defense load, I’m told) and a muzzle velocity of 1450 feet/sec (why do they call it muzzle _velocity_ when fps _doesn’t_ include a direction? It’s not a vector dammit!!). So I go to Rob’s reloading pages and plug these in to get a muzzle energy of 1000 J! (That’s **1000 J** , not 1000 J factorial.)
Is this reasonable? Has the .357 really got more than twice the muzzle energy of a .45 ACP and at least one-quarter more muzzle energy than the 10mm?!
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### Author:  [@Loopydude](https://boards.straightdope.com/u/Loopydude)
#### Post date: [February 29, 2004, 2:59am UTC](https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700/2 "2004-02-29T02:59:21Z")
Watch out. My topic got shut down for discussion of deadly stuff.
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### Author:  [@friedo](https://boards.straightdope.com/u/friedo)
#### Post date: [February 29, 2004, 2:59am UTC](https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700/3 "2004-02-29T02:59:58Z")
It’s reasonable to assume that the direction is “where the gun is pointing.” Ergo, a vector. 😉
As for the rest of your questions, I got nothing.
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### Author:  [@Una\_Persson](https://boards.straightdope.com/u/Una_Persson)
#### Post date: [February 29, 2004, 3:44am UTC](https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700/4 "2004-02-29T03:44:36Z")
Bullet muzzle energies are one of those things where there is a wide range of values that are possible, depending on the loading, bullet weight, firearm, and testing conditions and error. Plus, I’ve found that people often mix and match Joules with ft-lbf on charts and comparisons.
This calculator here shows the following energies.
From: [http://www.billstclair.com/energy.html](http://www.billstclair.com/energy.html)
9mm : 521J
.357 Magnum : 728J
.45 ACP : 532J
.44 Magnum : 1009J
This chart gives values in ft-lbf, but is useful for relative differences:
[http://www.chuckhawks.com/handgun\_power\_chart.htm](http://www.chuckhawks.com/handgun_power_chart.htm)
This one too:
[http://users2.ev1.net/~lertsman/Pistol-ammo.html](http://users2.ev1.net/~lertsman/Pistol-ammo.html)
See the wide range of values?
Look at this chart - see the difference between the columns “Lowest Factory Reported Muzzle Energy” and “Most Energetic Loading”:
[http://www.volny.cz/buchtik/Revo/Ballistic\_Info\_komplet.htm](http://www.volny.cz/buchtik/Revo/Ballistic_Info_komplet.htm)
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### Author:  [@Squink](https://boards.straightdope.com/u/Squink)
#### Post date: [February 29, 2004, 3:52am UTC](https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700/5 "2004-02-29T03:52:56Z")
> [@](#):
>
> (That’s 1000 J, not 1000 J factorial.)
A handgun firing bullets with the later energy would be suitable for blowing away Planets! Probably have a nasty recoil too. 🙂
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### Author:  [@Inky\_1](https://boards.straightdope.com/u/Inky_1)
#### Post date: [February 29, 2004, 3:56am UTC](https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700/6 "2004-02-29T03:56:04Z")
First off, “grain” is not the unit of weight used to measure the bullet, but rather it’s the unit of measurement for the gunpowder charge inside the cartridge that _fires_ the bullet.
So, it’s a simple equasion: Weight of bullet + Powder charge - varibles of energy loss in the form of things like the pistol’s blowback mechanism, the gap between the cylander and compression cone (in revolvers) and resistance from rifling and barrel length = Muzzle velocity. Since you haven’t stated the grain behind the .45, it’s hard to say, but in my experience that’s not unrealistic – .357’s are very high velocity because of the low weight bullet and high grain mix.
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### Author:  [@yoyodyne](https://boards.straightdope.com/u/yoyodyne)
#### Post date: [February 29, 2004, 4:07am UTC](https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700/7 "2004-02-29T04:07:47Z")
Bullet weight certainly is measured in grains. A grain is .0648 grams.
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### Author:  [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)
#### Post date: [February 29, 2004, 4:15am UTC](https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700/8 "2004-02-29T04:15:39Z")
All your numbers appear to be correct.
While a .45’s bullet weight is pretty high (around 230 grain), it’s pretty slow (around 850 ft/s). That only works out to about 500 J.
The .357 is a _magnum_ cartridge, which means quite a bit of powder is used to propel the bullet down the barrel (as compared to the bullet’s weight). Because of this, the .357 bullet is pretty fast – around 1500 ft/s. And since energy is proportional to v[sup]2[/sup], the .357 has quite a bit more energy than the .45.
But energy isn’t everything. Size also matters. Whether or not the .357 is more effective than the .45 is a matter of debate. Personally, I think _penetration_ (and thus bullet speed) is more important than bullet diameter.
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### Author:  [@wolf\_meister](https://boards.straightdope.com/u/wolf_meister)
#### Post date: [February 29, 2004, 4:24am UTC](https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700/9 "2004-02-29T04:24:02Z")
Want to convert foot-pounds to joules or other such energy units? Go to:
[http://www.1728.com/convenrg.htm](http://www.1728.com/convenrg.htm)
Here’s an index for all converters.
[http://www.1728.com/indexcon.htm](http://www.1728.com/indexcon.htm)
Hmmm maybe I should write an energy calculator which works with 3 variables.
(mass, velocity, energy)
When 2 are input, the third is calculated.
Incidentally, I have heard that for serious “stopping power” (mostly large game) a larger (or heavier) bullet is preferred over velocity.
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### Author:  [@gbrohman](https://boards.straightdope.com/u/gbrohman)
#### Post date: [February 29, 2004, 4:34am UTC](https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700/10 "2004-02-29T04:34:51Z")
For most of us shooters/reloaders the velocity is measured in Feet per second= fps the 1st measure is at muzzle. Lets take a .357 Magnum load with a 158 Grain Gr jacketed bullet Powder = Unique at 8.0 grains
Muzzle velocity = 1200 fps energy = 505 foot pounds ft. lbs.
at 25 Meters V = 1054 fps E = 454 ft. lbs.
at 50 Meters V= 1085 fps E= 413 ft. lbs.
These are test conditions depending on Gun= rifling twist rate/ barrel length/ primer/ case/ just about everything imaginable. with powder/ barrel length being high on the list. Powders are classified by burn rates and handgun powders are very fast burning powders. for proper performance the powder must burn completely before the bullet leaves the barrel. if its too fast and burns up before the bullet leaves the barrel, the bullet will start decelerating.
Reloading is a science, and not for everyone.
Hope this clears up some of your questions.
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### Author:  [@gbrohman](https://boards.straightdope.com/u/gbrohman)
#### Post date: [February 29, 2004, 5:00am UTC](https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700/11 "2004-02-29T05:00:42Z")
> [@js\_africanus](#):
>
> Is this reasonable? Has the .357 really got more than twice the muzzle energy of a .45 ACP and at least one-quarter more muzzle energy than the 10mm?!
The 10 mm has a Muzzle(M) velocity(V) of 1030 fps & M Energy of 425 ft lbs
The 40 s&w " " 990 " 390
the .357 Mag " " 1240 " 535
No the 357 doesn’t have twice the energy of the 10mm all these loads can have a different bullet, and comparing them are sometimes hard. The problem with the 10mm was recoil. The gun was hard to shoot in a small frame concealed carry gun. the 40 s7w is just a 10mm short if you will.
Bullet weight is sometimes measured in grams but usually in grains. example= 180 grains = 11.66 grams. Joules is very rare, maybe in a forensics lab.
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### Author:  [@danceswithcats](https://boards.straightdope.com/u/danceswithcats)
#### Post date: [February 29, 2004, 6:21am UTC](https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700/12 "2004-02-29T06:21:27Z")
My choice for a S&W 1006 over the .40 was simple-the .40 had a fatter grip, owing to the stagger clip design-the 10mm is inline and allows multiple concealed carry positions not afforded by the .40 weapon.
As far as the 10 being a hard to shoot weapon, that’s hogwash IMHO. I’ve gone to the range and after 3 or 4 bricks find it no different than if I’m using any other weapon.
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### Author:  [@Fish](https://boards.straightdope.com/u/Fish)
#### Post date: [February 29, 2004, 8:03am UTC](https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700/13 "2004-02-29T08:03:33Z")
> [@Squink](#):
>
> A handgun firing bullets with the later energy would be suitable for blowing away Planets! Probably have a nasty recoil too. 🙂
[Joe Piscopo from _Johnny Dangerously_]
This is an .88 Magnum. It shoots through _schools._
[/Joe Piscopo]
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### Author:  [@wolf\_meister](https://boards.straightdope.com/u/wolf_meister)
#### Post date: [February 29, 2004, 8:09am UTC](https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700/14 "2004-02-29T08:09:17Z")
Well I finished my energy calculator and it is located at:
[http://www.1728.com/energy.htm](http://www.1728.com/energy.htm)
I have tested it out with a few problems from this posting (as well as others) and it seems to be error-free. Then again, it is now 3:00 a.m. and I’m not at my sharpest mental capacity.
If nothing else, I caught an error in a posting by gbrohman -
a 158 grain bullet at 25 Meters; Vel = 1054 fps Energy = 454 ft. lbs
there’s something there that’s poted incorrectly.
Notice that at 50 meters, the bullet has sped up to 1085 fps.
Anyway, I hope you find the calculator useful.
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### Author:  [@matt](https://boards.straightdope.com/u/matt)
#### Post date: [February 29, 2004, 2:06pm UTC](https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700/15 "2004-02-29T14:06:06Z")
One thing to bear in mind is that recoil is proportional to **momentum** , which is bullet mass x bullet velocity (I’m going to ignore propellant gas mass and velocity, although that isn’t strictly valid.)
Muzzle energy on the other hand is half bullet mass x bullet velocity _squared_.
So if you double the bullet velocity and half the bullet mass, the recoil stays the same but the muzzle energy doubles. Of course, this means you need more powder in the shell, the barrel pressure increases etc. so there are practical limits. But a tiny bullet that screams out the barrel can have a lot of energy.
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### Author:  [@gbrohman](https://boards.straightdope.com/u/gbrohman)
#### Post date: [February 29, 2004, 2:33pm UTC](https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700/16 "2004-02-29T14:33:41Z")
Yes I was wrong. the 25 meter volocity should have read “1136 fps” the 1054 fps came from the 1100 fps muzzle volocity table. Sorry Sorry Sorry.
> [@wolf\_meister](#):
>
> If nothing else, I caught an error in a posting by gbrohman -
>
> a 158 grain bullet at 25 Meters; Vel = 1054 fps Energy = 454 ft. lbs
> there’s something there that’s poted incorrectly.
> Notice that at 50 meters, the bullet has sped up to 1085 fps.
>
> Anyway, I hope you find the calculator useful.
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### Author:  [@wolf\_meister](https://boards.straightdope.com/u/wolf_meister)
#### Post date: [February 29, 2004, 6:29pm UTC](https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700/17 "2004-02-29T18:29:49Z")
**matt**
You are quite correct about calculating recoil and muzzle energy. That is why a cartridge such as the .223 has great muzzle energy (and velocity) with minimal recoil.
**gbrohman**
And because of writing that calculator I discovered that error. (At first I thought it was my calculator). But that’s okay. No reason to apologize.
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### Author:  [@js\_africanus](https://boards.straightdope.com/u/js_africanus)
#### Post date: [February 29, 2004, 11:27pm UTC](https://boards.straightdope.com/t/gun-users-muzzle-energy-from-different-guns-these-numbers-cant-be-right/231700/18 "2004-02-29T23:27:05Z")
> [@matt](#):
>
> One thing to bear in mind is that recoil is proportional to **momentum** , which is bullet mass x bullet velocity (I’m going to ignore propellant gas mass and velocity, although that isn’t strictly valid\*\*.)
>
> Muzzle energy on the other hand is half bullet mass x bullet velocity _squared_.
>
> So if you double the bullet velocity and half the bullet mass, the recoil stays the same but the muzzle energy doubles. Of course, this means you need more powder in the shell, the barrel pressure increases etc. so there are practical limits. But a tiny bullet that screams out the barrel can have a lot of energy.
Okay, so equal & opposite actions has to do with the momentum and not the energy; i.e. momentum going _that way_ equals the momentum coming _this way_, hence the kick is bm_bv and not (1/2)bm_bv^2. Right? Cool, thanks.
> [@squink](#):
>
> A handgun firing bullets with the later energy would be suitable for blowing away Planets! Probably have a nasty recoil too.
Yeah, but people will claim _anything_ to make a sale.
**My error:**
I looked at the manual online again and those numbers are the _limits_ that the guns are manufactured to withstand, not the velocities for a typical load. So for the Federal [158 gr. .357 personal defense](http://www.federalcartridge.com/ammo30/handgun_show.aspx?loadid=C357E) cartridge, Rob’s calculator is giving me 731 J. However, that still isn’t telling me how much kick there is, thanks **matt** , and I can calculate that myself and compare to the .45 so I know what to expect. Thanks guys & gals!!
\*\*Did you hear about the guy who spent his life learning the horses so that he could win big? The numbers were too complicated to handle, so he got a physicist at a local college to do it. Taking the physicists results, he bet his was and was bankrupted in one day. He went to the physicist and demanded to know how he got his results, and the physicist said, “Well, I began by assuming a spherical horse.”