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treadlightly wrote:
There is bound to be more of an "oh, crud" factor to getting hit with 240 grains of .45 ACP than, say, the 80 grains of lead Granpappy's .32 rimfire pushed out of the muzzle at about the same velocity. The .45 ACP can be said to have more je ne sais quoi than the .32, and those who stoke their 1911's with clips call it knockdown.

To travel at the same speed as the .32, the .45 needs more energy to launch it. Of course it does have more energy, because it has a bigger case with more powder in it.

I read an interesting "knockdown" some years ago, but dang it I can't find the article any more. An off-duty cop in Chicago was providing security at a McDonalds that had been robbed more than once. One night a robber came in and the officer came out of the back to confront him. The cop reported that the robber fired a round at him, the cop felt it hit (abdomen I think, and this was before body armor became common) and he went down. But he had always told himself, mentally rehearsed may times, to "keep fighting." The cop fired from the floor, and killed the robber IIRC.

Anyway, the cop started examining himself, and was very surprised to find NO wounds. The robber's bullet had missed. Apparently in programming himself to keep fighting, he had also accidently programmed in that when someone fired at him, he would be hit and go down. And keep fighting.

9mm may expand but 45 don't shrink.

AndyC wrote:

johncanfield wrote:I don't want to start a caliber war but I wonder how my EDC Sig P239 in .357 Sig compares to a .45 round in knockdown power? I do own a 1911 and it's one of my favorite shooters, dear wife enjoys it as well

Well, knockdown power doesn't exist but for grins I calculated kinetic energies for these calibers, rounded up to 3 decimal places for easier reading:

230gr .45acp @ 900 fps:

230gr = 0.0149037 kg
900 fps = 274.32 m/sec
Ek = 560.763 Joules


115gr 9mm @ 1200 fps:

115gr = 0.00745187 kg
1200 fps = 365.76 m/sec
Ek = 498.457 Joules


125gr .357 Sig @ 1500 fps:

125gr = 0.00809986 kg
1500 fps = 457.2 m/sec
Ek = 846.564 Joules


Very impressive, huh? Not so fast. Let's take this object:

500gr = 0.0323995 kg
220fps = 67.056 m/sec
Ek = 72.842 Joules

Pretty weak, huh? Well... it's a 500gr broadhead arrow @ 220 fps.

As I've always said - ain't about the energy per se - it's how that energy is used to cause physical damage.

Fascinating analysis Andy! Roger on the Joules, 850 Joules impacted on a lower limb is trumped by a broad arrow into a major artery. However I really like having a bunch of Joules in my holster .

AndyC wrote:Absolutely - but my example is to illustrate that it doesn't require a lot of kinetic energy to do a lot of damage.

That was Lewis's theory!

As the great Ron White said you can't fix stupid.