Originally Posted by antelope_sniper
Originally Posted by denton
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Denton:

You posted:

"If your bullet impacts ...that point, penetration begins to decrease".

Sorry but I just don't understand. Something is getting lost in the interpretation.

Can/will you please elaborate ?


Sure. Let me have another try at it.

Here is actual average test data from 30-06 cup and core bullets impacting at various speeds

[Linked Image]

Most people are shocked that the curve slopes downward to the right, meaning you get less penetration as impact speed increases. Below about 2100 FPS, you get very deep penetration because the bullet does not open. Above about 2800 FPS, the bullet begins to fail, and penetration decreases. Between those two speeds, the length of the wound channel is about 15 inches, regardless of where in that window you are.

Partitions open at about 17-1800 FPS, and give about 16 inches of penetration regardless of impact speed above that point.

So more speed does not give you more penetration. In fact, if you're shooting something for big game with an MV above 3000 FPS, your bullets will frequently fail on shots within 100 yards or so, unless you use premium bullets.

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Denton, I have to disagree with you a bit.

A faster impact will give you a wider wound channel which can result in more internal damage then a long narrow wound channel. The wider the wound channel, the better the chance for a CNS hit, which is what produced most DRT results.

A 160gr bullet leaving the barrel at 3400 can have amazing on game effects.


You may well be correct about getting a wider wound channel. I'm still wrestling with that one.


Above 3k it's time to switch to a modern, bonded bullet.

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I won't argue with the post or the study. To be copasetic, however, I will say that I may not disagree with the findings but I will amplify that my "take" on bullet expansion, penetrations has been formulated over many years of field experience.

Again I will beat up on the bullet peddlers who are desperately searching for more and more malarkey, to run their jive on the unsuspecting potential customer. It's just plain and simple 90% hogwash. I don't buy it in a millisecond. Also again for the old Guys, please don't pay any attention to my opinions. These are not for you, these are for the young, inexperienced fellows who need to know the facts accurately and honestly absent all of the smoke and mirrors. At the risk of repeating myself I will say again that we could get rid of 90% of all cartridges, calibers and rifles and still have far more than any one of us could contend with in a lifetime. That means that if Ken Howell is right about 10,000, losing 9,000 still leaves 1,000 for you to tinker with. Not likely.

The above penetration study is missing some important details. While I don't denigrate it, I know from a lifetime of hunting that there are several aspects of penetration, effectiveness that need to be taken into consideration. What the study does illustrate is the desirability of matching bullet types with velocity.

But I'm a good sport. I don't want to rain on anyone's parade. If it is a turn on to debate the details that's just hunkey dorey with me and more power. Everyone's opinion counts. That's how we learn. Free exchange of ideas and opinions.

Last edited by William_E_Tibbe; 09/01/15.