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dgray64 08-11-2008 09:13 PM

Silly question maybe....
 
Why does a .40 S&W pistol shoot with more recoil and supposedly more penetration than a .45 APC? I was reminded of that again this weekend as I bought another .45. The .45 barks and makes a big hole while the .40 bangs and kicks back harder than the pistol with the bigger round. I'm just curious. Thanks for your input.

Dave :)

jeepcreep927 08-11-2008 09:40 PM

The .40 operates at a comparatively higher chamber pressure than the .45 ACP which I think accounts for the "snappy" recoil. Penetration is relative to a few factors like bullet design, weight, diameter and velocity. If this is a comparison of penetration period, not effective pentration (temporary wound cavity, permanent wound cavity) the smaller faster bullet will push deeper through a given material, not taking into account any expansion properties of a given bullet design, so say, both firing FMJ ammo. I am not an engineer though, so I will gladly bow to someone else if I am wrong.

G21.45 08-11-2008 10:09 PM

Quote:

Originally Posted by dgray64 (Post 35755)
Why does a .40 S&W pistol shoot with more recoil and supposedly more penetration than a .45 APC? I was reminded of that again this weekend as I bought another .45. The .45 barks and makes a big hole while the .40 bangs and kicks back harder than the pistol with the bigger round. I'm just curious. Thanks for your input.

:) My compliments! THAT is, both, an astute observation on your part as well as a very good question.

First, it’s not velocity. These two rounds aren’t that far apart. Both the 180 grain JHP 40 caliber bullet, and the 230 grain FMJ 45 acp bullet run at remarkably similar velocities.

Personally, I’m inclined to think that there are two principal reasons for the recoil phenomenon you’ve noticed: First, higher chamber pressure of 35,000 psi for the 40 S&W compared to 21,000 psi for the 45 acp. This increases the extent and duration of the peak pressure impulse. The higher the pressure, the greater the overall slide and muzzle recoil - both actual and perceived - is going to be.

Second, the 45 acp fires a large heavy low pressure bullet that is going to feel different as it travels down the barrel and exits the muzzle. I’m convinced that the acceleration impulse is different, too. It takes longer for the 230 grain 45 acp bullet to come up to speed; and, this causes that long, drawn out, recoil characteristic that is so very conducive to rapid accurate pistol fire.

Anyone who does a lot of pistol shooting quickly learns that there is, indeed, a sharp fast crack to firing the 40 S&W while there is a dialectically opposite slow heavy push to firing the 45 acp.

This is one of the principal reasons, ‘Why’ I only shoot 45 acp in all combat pistol courses, and exclusively carry this caliber pistol as a primary weapon. (Neither have I, ever, been slower or less accurate than the guy standing next to me firing, either, a 40 S&W or a 9mm.) ;)

More penetration? Here’s a gel test chart. Me? I don’t see any appreciable difference - Just the opposite, actually!

http://img229.imageshack.us/img229/1...oningelyi7.jpg

Good job! For a newbie poster you're doing very well. :D

dgray64 08-11-2008 11:56 PM

Thanks to both of you! My old brain gets a little foggy sometimes and I had a thought that I could change powders or do something different to make my .40s act like .45s, but that's not going to work. I think I'll just have to trade them both off and get another .45. Thanks again!!

Dave :):)

RL357Mag 08-12-2008 12:56 AM

Very important to this comparison also is the platform - a 1911 .45 acp weighs considerably more than my Beretta .40 mini cougar or a Glock .45. Heavy guns absorb more recoil rather than transfer it. Modern .40 cal auto's are made from alloys. The good ol' 1911 is solid steel. The .45 should produce more felt recoil firing a 230gr. projectile than the .40 shooting a 165 or 180gr. projectile, but again, the heavier 1911 will absorb much of it. I find it much more difficult to come back on target rapidly with the .40 Beretta because of it's snappy recoil.

genie 08-12-2008 01:31 AM

I find the "plastic" pistols definitely are more recoil-persuasive than full metal versions. I cite my Sigma .40 vs S&W 4006. The 4006 is all-steel, heavy, and comparatively, "feels" like a 9mm is being fired.

Therefore, I conclude weight of pistol, in comparing .40 to 45, also has bearing on this.

G21.45 08-12-2008 01:42 AM

:) Can't really say that I agree with any of this. My G-21's clearly produce a lot less recoil with any ammunition than either one of my Colt 1911 Mark IV's. There are, probably, two principal reasons for this: (1) The bore axis on the Glocks is considerably lower; and, (2) 13 rounds of 45 acp adds a whole lot of extra weight to the frame. ;)

RL357Mag 08-12-2008 02:23 PM

Quote:

Originally Posted by G21.45 (Post 35779)
:) Can't really say that I agree with any of this. My G-21's clearly produce a lot less recoil with any ammunition than either one of my Colt 1911 Mark IV's. There are, probably, two reasons for this: (1) The bore axis on the Glocks is considerably lower; and, (2) 13 rounds of 45 acp adds a whole lot of extra weight to the frame. ;)

You're probably right about thge magazine capacity. My Beretta .40 has two mags - one shorter 8 rd. and one longer 10 rd. Even with the 10rd. mag it's recoil is much more pronounced than the 1911 with 7 rds. because the Beretta is all alloy and plastic.

robocop10mm 08-12-2008 03:06 PM

All observations are likely valid. Felt recoil is a product of bullet/powder weight and velocity vs the weight of the weapon. Most .45 pistols are heavier than their .40 counterparts thus have lower perceived recoil. Pressure may have some influence as does moment of unlocking (varies from gun to gun, round to round) and slide velocity. You may have different recoil characteristics with a fully loaded magazine (first round fired) and empty magazine (last round fired).

G21.45 08-12-2008 03:52 PM

:) Very good points, robocop10mm! Mechanical unlocking is certainly involved - as is slide speed. Glock's, 'modified Browning lockup' is weak; and slide speed, across most of the model line, is consistently too fast and often needs to be slowed down.

With the exception of the 9mm models all Glocks are notoriously under-sprung. They have to be in order to guarantee reliability. If Glock's standard springs weren't so light, polymer frame flex might prevent reliable feeding altogether.

(Polymer frame flex and excessive slide speed are two reasons, 'Why' the factory always recommends heavier magazine springs (or modified followers) in order to cure feeding problems - especially in the 40 caliber models!)

Yes, there is also a noticeable difference between a pistol with a fully loaded, and a mostly discharged magazine. It's something that you learn to compensate for while firing; and, if you use an Arredondo magazine extension like I do, the difference in frame weight is huge!


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