ORIGINAL: bigbulls

Nearly identical isn't identical is it?
Go shoot a 350 grain arrow and a 500 grain arrow out of the same bow through a chronograph and calculate the KE numbers and tell me which one has more KE. The 500 grain arrow will have aproximately 1 - 3 more foot pounds of KE.

Look at a rifle since it is dealing with far greater forces than a bow and the results are much more noticable.

Assume 55,000 PSI chamber pressure a30-06 will fire a 180 grain bullet at a lower velocity than it will a 150 grain bullet but the 180 grain bullet will have aproximately 100 foot poinds more KE at teh muzzle than the 150 gran bullet. That 55,000 psi is able to do more "work" on the heavier bullet becasue the forces are being applied over a longer period of time.