Originally Posted by Terry_P
I think that using energy as the determining factor doesn't tell the whole picture as energy is velocity dependent. A 38 special has a heavier bullet with a larger diameter and will penetrate to a vital whereas a 22 LR is problematic for penetration.
I agree with you Terry. Penetration is a function of an object's momentum and frontal area. Let's assume the front area is negligible, and agree that momentum is a function of Mass times Velocity. Although an object may have a MUCH higher energy, it may actually have a much lower momentum due to the fact that energy is a function of Velocity squared while momentum is a one-to-one relationship. The .38 would definitely penetrate more at 20 feet. The .22, I believe but am not positive, would use up its energy to disintegrate and fragment in shallow tissue while not penetrating far at all (even if it did stay intact).
For example, the momentum of the .38 at the muzzle assuming my previous velocities and weights is nearly 2 times that of the .22 rifle at the muzzle, even though there's only a 3% difference in energy.
Originally Posted by delta13soultaker
Pony you're a smart dude and I'm not preaching to you. Just want to explain in my humble opinion why numbers in this instance are highly decieving.
While I appreciate that Delta, I'm not that smart and consider real-world testimony such as your own much more important than my math. I agree that the numbers are very deceiving and we just need to keep that in mind. I believe you're absolutely right in what you posted but thought that the energy level similarity was pretty interesting.
I noted above that momentum and energy are VERY different with momentum often times playing a bigger role in terminal injury than energy. I think that energy only becomes more important when a projectile totally disintegrates, creating a massive wound cavity (essentially exploding on impact). When you're talking about a .22 LR bullet that just breaks up at higher energy, vs. a .38 that holds its weight, momentum of the .38 is probably much more important to terminal effectiveness. Now, when you start debating a .223's velocity/weight ratio to a 7.62x39's velocity/weight ratio the issue get's a LOT more complicated because both provide a huge amount of destructive energy on impact and momentum is less important when dealing with effects on personnel since both could easily penetrate fully through a person with ease.
Thanks for the feedback Delta, and I don't mind preaching at all, as we all have a lot to learn...