Shot placement, shot placement, shot placement..

[sm]

Hey Preacherman,
Do you have and can you post the #'s for the 9x23, 38 Super and .357 ( wheelgun), to add to comparisons earlier?

Thanks.

 

[Nightcrawler]

It's quite simple. You just multiply the mass in grains by the velocity in feet per second. .308 ball (147 grains @2700 fps) has 396,900, whereas .223 Remington (55 grains @ 3100 feet per second) has 170,500.

Increasing the bullet weight generally dramatically increases the momentum. A bullet with more momentum will require more force in the opposite direction in order to stop it; in other words, it'll penetrate more. (This, of course, doesn't take into account bullet design).

 

[Jeff White]

Preacherman,
I have to respectfully disagree with you on momentum. To stop an assailant in the most expediant manner you have to depend on one or two things. A central nervous system hit or rapid ex-sanguination. The body does a very good job of protecting the central nervous system. A good hit to the CNS is very hard to achieve. This leaves us with ex-sanguination. The objective is to cause rapid blood loss in large enough quanity to disrupt the flow of oxygen to the brain causing it to shut down. To reliably do this you need a bullet that will penetrate 13 inches and make the largest permanent wound cavity as possible. You need the 13 inches of penetration to reach the blood rich internal organs from any angle. Gunfights don't happen on the square range and you will likely have to shoot through a forearm or bicep to reach the internal organs.

There are loads in all the major calibers (.38 spl -10mm) that will accomplish this. As Nightcrawler said, bullet construction has a lot to do with this. A bullet moving at 1400 fps that expands and stops after 6-8 inches of penetration will not be as effective as one moving at 950 fps that gets you the 13 inches of penetration. Momentum only figures into this as it applies to getting the projectile deep enough into the body to reach the vital organs.

It's basic physics, any projectile that struck hard enough to knock a man off his feet or even off balance would have the same effect on the person who shot it unless it was fired through a recoiless rifle type design that vented all the recoil energy into the air.

You can move the Winchester 115 gr JHP 9mm at 13-1400 fps out of a 4"barrel and get performance that is comparable to .45 ACP 230 gr ball at 950 fps. Which is better? Who knows? We can argue about that forever. This is where the other factors figure into the equation. Maybe you prefer a thrid generation S&W 9mm auto over a 1911? It doesn't really matter. You can accomplish the same thing with either weapon. There are effective defensive loads in all calibers from .38 spl to 10mm. Pick what you are comfortable with and shoot the best, then do some research and find what load gives you acceptable performance in your chosen weapon.

Jeff