From my experience, the behaviour of fragment penetration ends up somewhere in the gut, making a mess.

I am sitting on a mountain in Colorado Elk hunting in deep snow. It started off -22 that morning and the high was -2. I sat in my honey hole until 4:00 and suddenly there appears 20 Elk at 280 yards up the mountain, the biggest a 5X5 Bull. I am shooting a .340 Wby with 250 grain Barnes XLC, or if you know Barnes the old blue bullet. The speed of the reload around 2950 fps. I fire just behind the shoulder and when the snow settles from the muzzle break I see the huge 5X5 Bull standing with his opposite shoulder to me. I fire again just behind the shoulder and he flops down. After an hour of climbing to the Bull it was dark and I had a big job of gutting. I found two bullet holes from opposite sides within two inches of each other. I got the job done and left the Bull on the mountain with the body cavity spread as wide as possible filled with snow. The next day my son and a buddy brought the Bull down the mountain and showed me five blue coated petals off the bullets. He found 3 petals in the skin of one exit hole and 2 petals in the skin of the other exit hole on the opposite side. I considered the bullets performed perfectly, doing their job blowing through and shedding the petals at the last on the sides of the exit holes. I could picture the bullets burning, twisting and causing maximum damage all the way through the Bull, then blowing out and spraying blood and gore all over the snow beyond. Once again I felt the bullets performed their job perfectly. My son and our buddy were very impressed with the results. After reading this account you draw your own conclusions. Good shooting.

When it comes to bullet performance in live animals, you hope for the best, but with any bullet you may get a surprise now and then..Todays bullets are the best I have ever seen, and its been a long time since I have had or witnessed an out and out failure..Some so called failures are not failures at all, sometimes a lack of knowledge blames bullets for failing such as caliber size exit hole being the worst contender when in fact it may have caused all manor of internal destruction as the bullet came apart and seperated leaving only the base to exit...The H mantle that has a great long term reputation is designed to do exactly that.

Match bullet construction and velocity to the caliber and the game and you will seldom have a true failure, mayby never. If you use a monolithic HP, then use a lighter than normal weight such as in the 06, use a 150 monolithic as opposed to a 180 cup and core..Seems to always work..

"Some so called failures are not failures at all, sometimes a lack of knowledge blames bullets for failing such as caliber size exit hole being the worst contender when in fact it may have caused all manor of internal destruction as the bullet came apart and seperated leaving only the base to exit.."

Great point for sure!

quote:

Originally posted by ALF:

Here both the penetrator ( bullet) and target are likened to a fluid i.e. a fluid penetrating a fluid.

Absolutely. Bullets may be solid in form but they do indeed exhibit fluid behaviour.

quote:

Originally posted by 900 SS:
I dont think hydraulic force is needed to open TSX or similar bullets. If you shoot them into wood, across or along grain, they still open up like supposed to.

If fluid force is not needed in the nose cavity for HP monomental expansion, then what act of physics is responsible for the displacement of copper/formation of petals?

On HV impact,
Would not the parallel wall HP tip cavity be the higher pressure side - and the opposing curved surface[outer HP tip surface] be the lower pressure region?

The natural inclination then , would be for the copper to begin to move-displace in the direction of the lower pressure region.[path of least resistance]
(just think of how aircraft get lift-movement, through the wing)

quote:

Originally posted by 416Tanzan:

a monometal will not explode like frangible lead core bullets. They may bend but they will hold together.

A copper mono-metal shank remains ductile and simply deforms under high stress, but a brass mono-metal can break in half through the solid shank.

quote:

Originally posted by 416Tanzan:
a plastic tip would be better than a bronze tip due to light weight and malleabilty.
Still, there is always the possibility of closing a nose, whether monometal or lead-core bullets.

Id say save pointed add-on nose cones for things that really need them - like fighter jets,
and avoid them in objects like expanding HP bullets.