James B

The velocity and penetration make sense. The more velocity you have the more expansion you get. The more expansion you get, the less penetration you get. This holds true even more when you are looking and light bullets per caliber. Sectional density is the bullets ability to hold together and continue to penetrat. Add Momentum and you get an idea of why some bullets and or calber size are more effective. With weight comes momentu. Its harder to stop a freight train than honda. When you add velocity and a fast twist rate then you really put pressure on the bullet and at some point or speed the bullet will fail. The less sectional density, the sooner it will fail. Reading on the Corbon site and or other sites talking about even cast bullets. A 45-70 bullet of 400 or so grains will penetrat further when fired at 1700 fps than the same bullet will if fired at 2000 fps. Expansion and the bullets inability to hold a staight path will limit its penetration. Put a heavier bullet in a 375 H&H then slow it down and you get much better penetration. Velocity is important but it has its usefull limits. Bullet construction is important but you have to have momentum. It all works together.