Bullet Penetration Chart

[denton]

A few years ago, Handloader published the results of an experiment done on 180 grain 30-06 bullets. The question to be answered was how well different brands of bullets hold up when fired at wet phone books at various speeds. I have taken just some of the data out of the chart, and made it into a graph. Each point is the mean penetration of three bullets. Vertical scale is penetration in inches. Horizontal scale is impact speed in feet per second.

[fabsroman]

While penetration is a good thing, what really matters is energy deposited in the target. I use the Barnes X bullets for most of my hunting and haven't had a problem with them, but I am willing to bet that a FMJ bullet would go through a lot more than the Barnes X bullet. I read another test where Barnes X bullet and I think Trophy Bear Claw bonded came out on top. In that one, they were shooting into 1 gallon jugs of water and see how much penetration and damage was done to the jugs. I also think they used ballistic gelatin in that test.

[HPBTMTCH]

Not nessasarily fabs, an FMJ often times will become "U" shaped and tumble. A faster twist helps penetration somewhat as well, And it becomes even more so when going through steel.

[fabsroman]

I thought the whole reason behind the FMJ was to prevent those types of wounds in soldiers. I guess I am wrong.

[Skinny Shooter]

Hey, there aren't any Matchkings on that chart

[BILLY D.]

Originally posted by fabsroman
I thought the whole reason behind the FMJ was to prevent those types of wounds in soldiers. I guess I am wrong.

fabs

pistol bullets maybe. rifle bullets a whole different ball game especially if they hit bone and start to tumble. they leave a real nasty wound channel. if they merely hit muscle or fat it's in one side and out the other. with minor damage unlees it clips a major artery.

[fabsroman]

I didn't know that. I had heard of M-16 bullets tumbling, but merely thought it was because of the small, light bullet, travelling super fast at close range. I guess it makes sense that the bullet would tumble if it contacts anything the least bit solid.

[denton]

It's actually even a bit more subtle than that.

There are conditions for stability in a gyroscopically stabilized object. They have to do with rotation speed, length, and diameter. A system is "stable" if it will return to its original state, given a small perturbation. A weight hanging from a string is stable. A pencil balanced on its point is unstable.

The 223 bullet is deliberately designed to be right on the brink of instability. As soon as it strikes something, it tumbles. It's designed to do that. When an FMJ 223 bullet hits a person, it causes a much worse wound that a stable bullet of the same size would.

The Warsaw Pact countries howled bloody murder over this violating international law. They continued right up until the time that they developed their own equivalent bullet.

[fabsroman]

Denton,

It took me two reads, but I finally understood that concept. So, the .223 FMJ bullet is worse than other bullets as far as the tendency to tumble is concerned.

Is that because they make the bullet longer and bottom heavy? Kind of like the pencil?

[denton]

Fabs, I did major in physics, but it was a LONG time ago, and I haven't had much reason to apply the math of stable and unstable equilibrium since then.

Yes, the fundamental idea is that the dimensions, and rotation speed, were deliberately chosen so the 223 military round would tumble on entry. Exactly how they did that... I don't know. I do know that the Warsaw Pact absolutely howled over it, saying it was unfair, etc. Then they developed their own version of it, and the howling stopped.

Of course, for hunting, most of us want something a little more stable, so the bullet will push the mushroon through the wound channel. That is even more destructive.