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Guest grimel
Posted (edited)
I'm confused, I thought kinetic energy was weight times velocity?

124 x 1200 = 148,800

230 x 900 = 207,000

You thought wrong. KE = 1/2mv^2

Edited by grimel
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Guest bkelm18
Posted

Weight times velocity is Momentum.

Guest grimel
Posted
Oh I see now you were confusing foot pounds of energy with kinetic energy. But even in foot pounds you are wrong.

230g at 900 fps = 413.6 FPE

124g at 1200 fps = 396.42 FPE

Here is a cool link to use to calculate about everything.

ENERGY CALCULATOR

:D

Well, FMJ 45acp runs more like 830-850 at best dropping KE to under 360 and NATO spec is 1250 +/25 so the minimum for 124gr 9mm NATO is 413fpe.

So, again, I'm not wrong or confused.

Posted
You thought wrong. KE = 1/2mv^2

No I'm not.

where M is the mass and V is the speed of the body. In SI units (used for most modern scientific work), mass is measured in kilograms, speed in metres per second, and the resulting kinetic energy is in joules.

So if you want to talk in kilograms and Joules.

230g at 900fps = 560.76 Joules

124g at 1200fps = 537.47 Joules

Posted
Well, FMJ 45acp runs more like 830-850 at best dropping KE to under 360 and NATO spec is 1250 +/25 so the minimum for 124gr 9mm NATO is 413fpe.

So, again, I'm not wrong or confused.

Well we can move the fps around how ever you want but all the published data puts them roughly at 900 and 1200.

Posted

Bottom line, the 45 will hit harder and we don't need math to prove it. Just take a couple of glocks in 9 and 45 and shoot them back to back and see which one recoils more. Every action has an equal and oppisite reaction. Same reason a 30-06 kicks more than a 243.

Guest Muttling
Posted
When did we stop carrying NATO 9mm? If we are still using NATO standard 9mm when did NATO stop using 115/124gr at 1200fps 9mm and drop to some bullet at 850fps? BTW, 9mm NATO has more k.e. than 45 ACP (400+ fpe vs 320fpe). Oh, as for penetration, given the same bullet design (RN FMJ) the NATO 9mm has a higher sectional density, thus, will penetrate better. This is simple physics.

No problem. You carry that 9x19 and keep telling yourself that it's more potent than a .45 ACP.

My experience says that the larger calibers hit harder unless the round is moving REALLY fast and that's what I'm going on. But that just me and my choice.

Guest MCRAIG
Posted

I didn't know so much math was involved in handgun posts, I should have showed up to physics more often.

Posted

in semiautos the larger caliber will always hit harder period. same goes in revolvers. but i you cross them, you have some overlapping. .357mag hits harder than 9mm even though its very close to same bullet. .327mag hits much harder than .32acp. .41mag hits much harder than .40S&W. .44mag hits harder than .45acp. .45colt hits harder than .45acp. and so on and etc.

thing is you have to decide how much you want to carry. a .22 will kill with proper shot placement and so will a .500S&Wmag. you just have to pick a caliber and platform in between that suits YOU and go with it.

me personally, i am the king of over-kill. for now i choose the .45acp as my caliber. but when funds are available, i will probably be carrying the new S&W 329PD scadium-frame .44mag revolver from time to time when appropriate. its weighs less than a steel 1911, quite a bit less.

i think that we all know, at least we should, that unless we face special circumstances, anything 9mm or bigger will stop what we face as civilians. but do you want to be prepared for those special circumstances(drugged up assailant, multiple assailants, assailant w/ body armor, etc.)?

no matter what, there is the law of diminishing returns that comes into effect. how about that story of a man and his family and friends that got attacked by over 50 gang members? what are you going to carry daily even in your own backyard to counter that? most agree you need 2 rounds per person, thats over 100 rounds of weight plus the gun. we have to reach a compromise of what we are willing to carry and what we should need. do you want high-capacity or would you rather have half as many rounds of twice the diameter?

i cant knock on anybody for carrying anything because its better than leaving it at home in the safe. the best caliber you can carry is the one you have on you when you need it.

Posted (edited)

9mm hitting as hard as .45 is a joke. Anybody who has ever shot an IDPA match can tell you this. Why? Because when the .45 bullets hit the steel poppers, they fall QUICKLY. When the 9s hit the poppers, they USUALLY fall. Shoot one on the edge or low with a 9mm, and it's often still standing. The sensitivity of the targets can be adjusted, but .45s easily outclass the 9s. Also, in IDPA, the CDP division is 8 shot .45s (mostly 1911s), and their ammo must meet a 165,000 power factor. Power factor is calculated the same as momentum--bullet (in grains) X velocity (fps). A fairly hot 9mm load is a 115 @ 1200 fps (show me a factory 124 @ 1250 and I'll pay for the ammo). Power factor = 138,000. A typical .45 is 230 @ 850, which comes up to 195,500. No comparison. Kinetic energy, on the other hand, SQUARES velocity, giving lighter, faster bullets a theoretical advantage. Velocity in fps (squared) X bullet weight in grains/450240. Who came up with the 450240? My guess is some guy who thought 9mms were the bomb. KE for above 9mm load = 367. KE for above .45 load = 369. So, KE says they are equal. Go shoot some steel knock-down targets, and you may disagree. I think KE is crap. Now I have to go clean my Glock 9mm--there's another match this weekend. :tough:

Edited by deerslayer
Guest grimel
Posted
No I'm not.

where M is the mass and V is the speed of the body. In SI units (used for most modern scientific work), mass is measured in kilograms, speed in metres per second, and the resulting kinetic energy is in joules.

So if you want to talk in kilograms and Joules.

230g at 900fps = 560.76 Joules

124g at 1200fps = 537.47 Joules

Yes you are still wrong. You can try to sound as if you have a clue by bringing SI into it; but, you still don't have the right results.

Same thing. For our purposes anyway.

For someone trying to sound educated by bringing SI into the discussion, you are making a gross error. Momentum isn't the same as kinetic energy.

Well we can move the fps around how ever you want but all the published data puts them roughly at 900 and 1200.

No, the published data for 45acp is 830 and the NATO specification (low end is 1225. Since velocity is squared, raising one 70fps and dropping the other 25fps is a significant change.

Bottom line, the 45 will hit harder and we don't need math to prove it. Just take a couple of glocks in 9 and 45 and shoot them back to back and see which one recoils more. Every action has an equal and oppisite reaction. Same reason a 30-06 kicks more than a 243.

Again, you don't know enough about physics to argue the point. The recoil has about zero to do with the energy of the projectile. Otherwise, my Sc 38spl with +P has much more energy than my Contender using my 30-30 barrel.

Keep trying to avoid the physics and shifting the numbers to your advantage. I was generous in favor of the 45acp with my rounding. If you take the published numbers the 9mm comes out even further ahead on KE (the orginal item in question).

Guest grimel
Posted
9mm hitting as hard as .45 is a joke. Anybody who has ever shot an IDPA match can tell you this. Why? Because when the .45 bullets hit the steel poppers, they fall QUICKLY. When the 9s hit the poppers, they USUALLY fall.

(show me a factory 124 @ 1250 and I'll pay for the ammo).

A typical .45 is 230 @ 850,

Velocity in fps (squared) X bullet weight in grains/450240. Who came up with the 450240? My guess is some guy who thought 9mms were the bomb.

Does anyone understand the difference between energy and momentum? Using a test designed for momentum has about zero to do with energy.

Buy Mil-surp or mil spec 124gr ammo.

Funny how the factories claim their 45acp is 830fps.

The 450240 is a conversion factor. It was "thought" up by some geek doing unit analysis.

Guest Muttling
Posted (edited)

I am a bit confused. Are you trying to make an actual point or just trying to continue an argument for the simple purpose of argument???

If you are making a point, what is it??????

For example, my point is very simple. Round for round, the .45 ACP hits a LOT harder than the 9x19. That's my story and I'm sticking to it.

Edited by Muttling
Guest grimel
Posted
in semiautos the larger caliber will always hit harder period. same goes in revolvers. but i you cross them, you have some overlapping. .357mag hits harder than 9mm even though its very close to same bullet. .327mag hits much harder than .32acp. .41mag hits much harder than .40S&W. .44mag hits harder than .45acp. .45colt hits harder than .45acp. and so on and etc.

WTF? I guess a 45acp hits "harder" than a 10mm?

Which hits harder 38 auto or 38 super or 9x21 or 9x17 or 9x23? 45acp or 45gap or 45 super? 44 auto mag or 45 acp?

Oh, and what constitutes harder?

Posted
Does anyone understand the difference between energy and momentum? Using a test designed for momentum has about zero to do with energy.

What is the difference? Are energy and momentum not two words for basically the same thing? They are two formulas designed to calculate how "hard" a bullet hits. IMO, one is more realistic than the other.

Guest grimel
Posted
I am a bit confused. Are you trying to make an actual point or just trying to continue an argument for the simple purpose of argument???

If you are making a point, what is it??????

For example, my point is very simple. Round for round, the .45 ACP hits a LOT harder than the 9x19. That's my story and I'm sticking to it.

My point is that is pure unadulterated bull*****. It is a freakin' service handgun round. IOW, they are all *****. A difference of 50fpe (NATO 9mm vs 45acp) is a big zero in terminal effect. Put the little pill where it belongs and the result will be the same for both.

Switch to expanding ammo, and the results for service rounds are the same. The bullet to bullet variations are greater than the difference between rounds. The choice of projectile with regards to penetration vs barriers provides a difference for LE.

For the record, shot placement is the ONLY thing that has a significant difference in terminal performance among service rounds.

Posted
WTF? I guess a 45acp hits "harder" than a 10mm?

Which hits harder 38 auto or 38 super or 9x21 or 9x17 or 9x23? 45acp or 45gap or 45 super? 44 auto mag or 45 acp?

Oh, and what constitutes harder?

10mm is the magnum semi-auto pistol round, of course it hits harder than .45acp

.45super hits harder than acp or gap. not sure on 44auto mag vs. 45acp but nobody uses 44auto mag as SD round anyways.

not sure on your 38 and 9mm group but i would guess the 38super or 9x23 as they have the longer casing and have higher case capacity for powder.

oh, and harder means how much force it translates into the target, not how much it will penetrate.

its not possible for a 3lb. sledgehammer to apply the same force as a 5lb. sledgehammer when you have the same man swinging it.

Posted
Yes you are still wrong. You can try to sound as if you have a clue by bringing SI into it; but, you still don't have the right results.

For someone trying to sound educated by bringing SI into the discussion, you are making a gross error. Momentum isn't the same as kinetic energy.

No, the published data for 45acp is 830 and the NATO specification (low end is 1225. Since velocity is squared, raising one 70fps and dropping the other 25fps is a significant change.

Again, you don't know enough about physics to argue the point. The recoil has about zero to do with the energy of the projectile. Otherwise, my Sc 38spl with +P has much more energy than my Contender using my 30-30 barrel.

Keep trying to avoid the physics and shifting the numbers to your advantage. I was generous in favor of the 45acp with my rounding. If you take the published numbers the 9mm comes out even further ahead on KE (the orginal item in question).

First you were the one to change the numbers that you posted not me. Secondly, winchester white box chronos out of my 1911 with a spread from 897-920 fps depending on the day and conditions. My handloads will reach 900 very easily without pushing the pressure at all.

You were the one that referred to foot pounds and KE in the same sentence as if they were the same thing. Not me.

Both KE and momentum are ways to consider energy of a moving object and that is why I said "same thing for our purposes".

My example of recoil was fine. I said take "two glocks" (they weigh the same basically) then shoot the two calibers, that way you can feel the energy comparison. So why don't you load your 30-30 round in a snubby (wow imagine that gun) and see what recoils more.:)

But I would love to see your math. Here are some conversion tables and if you use your original numbers you will get the same answers I did.

Kinetic Energy Calculator

Grains to Kilograms Conversion Calculator

CalculateMe.com - Convert Feet per Second to Meters per Second

:tough:

Posted

If you have single shot I would definitely have a 10mm, 50 GI, or 44 mag, but since I carry daily here is my reasoning. Again, it is all about compromises.

BTW - I'm not sure where some of you studied math and science but you may want to crack the books again.:tough:

Because it is not as fat as the popular .40 and .45 caliber cartridges, a double stack pistol for 9x19 can hold between 50% and 100% more cartridges. The slight energy advantage held by the larger caliber per shot (345 ft. lbs. for the 124 grain 9mm slug compared to 370 ft. lbs. for the 230 grain .45 slug) does not come close to making up the difference. The shooter with a 15 shot 9x19 pistol in his hand controls 5175 ft. lbs. of muzzle energy, which he can deliver to any number of targets between 1 and 15. The shooter with a 7 shot .45 ACP pistol can deliver only 2590 ft. lbs. of muzzle energy to between 1 and 7 targets. This is one very good reason why the U.S. Army adopted the 9x19 and the Beretta M-9 pistol in 1985.

All during the post-WW II years from 1945 to the 1990's there were a tremendous number of articles and books written by supposed experts alleging the superiority of the .45 ACP over the 9x19. These assertions were usually based on theoretical models of stopping power (like the Cooper "short form") that suggested a large .40 or larger caliber bullet had some intangible advantage in stopping power irrespective of the actual energy delivered. These theoretical models seriously over estimated the stopping power of the .45 ACP and seriously underestimated the stopping power of the 9x19. Assertions that .45 ball (FMJ) ammunition was 90% effective in achieving one shot stops were common. The truth revealed by the 15 year Marshall-Sanow study of thousands of actual shootings is that standard 230 grain .45 ball ammunition is about 62.89% effective, and 9x19 115 grain ball ammunition is 62.26% effective in achieving a one shot stop.

More important to civilian and police shooters is the effectiveness of the best bullets in the calibers, which for most purposes are expanding JHP bullets. The top load for the 9x19 is the Cor-Bon +P 115grain JHP, which is 91% effective in achieving a one shot stop. (For comparison, the top load for the .45 ACP is the Federal 230 grain Hydra-Shok, which is 92% effective.) The 115 grain +P loads from Federal, Remington, and Winchester are all close, averaging about 89% one shot stops.

Guest grimel
Posted
What is the difference? Are energy and momentum not two words for basically the same thing? They are two formulas designed to calculate how "hard" a bullet hits. IMO, one is more realistic than the other.

No, they are not the same thing. They do not calculate the same thing. They are not designed to calculate how hard a bullet hits. Neither is more realistic than the other.

Kinetic energy in simple terms is the energy of an object based on it's speed. Momentum is an objects resistance to change of speed (again in simple terms).

KE=1/2mv^2 while momentum (P) is P=mv.

Last I checked, 1/2mv^2 doesn't equal mv; thus, they aren't the same thing.

Your opinion has about as much weight as my opinion, OTOH, more than a few people have been researching this for some time (doc roberts pops to mind). These folks who are trying to find what actually works instead of following the oft repeated myths come to amazingly similar conclusions - handguns suck, long guns rule. The only reason to use a handgun is you can't use a long gun. Given premium expanding ammo, service handguns perform equally well, given FMJ they perform equally poorly. For a handgun, shot placement (given adequate penetration) is the only thing with significant merit.

Given scientific data, the choice in handguns becomes what one shoots the best and what one can shoot effectively weak hand only (the "worse" case).

Is that any clearer?

Guest grimel
Posted

oh, and harder means how much force it translates into the target, not how much it will penetrate.

That is YOUR definition. What is THE definition.

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