I am not going to shoot holes, deep penetrating or not. But here's some questions for you.
I generally agree with what you say, though I don't think the intent of those tests, which I haven't seen are necessarily to test the absolute penetrating ability of those bullets so much as they are merely to compare the different bullets and loads with one another. Of course that's why a test medium is used to begin with, in an attempt to produce reproducable results. That is, to remove the variable of the test medium itself.
Naturally the problem comes in right away when someone doesn't think the test medium is realistic, always a valid objection. I imagine that a tester would like to have something that does replicate the presence of bone in the path of the bullet, or for that matter, clothing, armor, leather, arms, etc., etc. There are limitations in these testing in the way of cost, time and "what do we include?" That's another way of saying that the testing can't go on forever. Another factor they might have considered is that bone, or something resembling bone, creates secondary projectiles within a body and they may have wanted to avoid introducing a complication like that. And in the case of a head shot, the testers may have also decided that anything would work then (unless it didn't), which is sometimes mostly true.
Just about anything else is iffy and besides, a man can be seriously incapacitated if hit in the leg. Would it stop the fight? Beats me!
Shoot low, sheriff. They're riding Shetlands!
Underneath the starry flag, civilize 'em with a Krag,
and return us to our own beloved homes!
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