Distance plays a role in how much wounding will occur. Most bullets fired from handguns have lost a significant amount of KE at 100 metres, while high-velocity military rounds still have a good proportion of KE at 500 metres. Military and hunting rifles are designed to deliver bullets with more KE at a greater distance than handguns and shotguns. The speed at which a projectile must travel to penetrate skin is about 50 metres per second and to break bone is around 65 metres per second, which is considered quite low. The Hague Convention of 1899, and later the Geneva Convention, forbade the use of expanding, deformable bullets in wartime.
Military bullets have full metal jackets around the lead core.
Then again, modern military assault rifles need to fire bullets at high velocity, so the bullets have to be jacketed in any case because the lead would melt. All rights reserved.