Look at the way a military FMJ is made, particularly those designed for full sized cartridges like the .303, .30/06 etc. the bullet is a spitzer so the largest percentage of weight is at the base of the bullet, in fact there was a .303 bullet that even had a wood plug in the cavity between the lead core and the bullet nose to maximize this situation. Another consideration is that a bullet seldom if ever hits point on, as it flies in a yaw. So, you have this butt heavy bullet, flying in a yaw relitive to the target, and that bullet suddenly meets resistance, like a man's chest for instance. What happens? Well the bullet swaps ends, and now you have an exposed lead base facing forwards, or maybe not, because the jacket is purposely weakened at the cannelure so it breaks in two. Now you have two bullet tracks tearing around inside ripping up tissue, organs and blood vessels.
If you want to get around the Hague Convention, this is how you do it. I used to have quite a collection of military FMJ's that I had collected over years of shooting. Many, though not all, were bent in half, and ready to break in the manner I described.
It is interesting that a solid designed for big game hunting is a good killer where as the military FMJ is a horrendous wounder. The solid, when properly designed, is short for caliber, has parallel sides and a hemispherical or blunt nose. Penetration is solely a function of velocity when the bullet cannot upset, so the faster the bullet goes, the deeper it penetrates.
Neither are cast rifle or handgun bullets designed to expand, yet with flat noses they penetrate well, and have a reputation of producing clean kills.
