Good point 9.3X57.

From my days of fooling around with a stout 50 caliber bolt gun, I have left over 50 BMG bullets that I cut down, Harold Johnson style, turned around and essentially shot the bullets "boattail" first. Some of the bullets were steel core and gliding metal jacket, some steel core with a washed copper steel jacket, some were lead core with gliding metal jacket, some were solid bronze. My thinking is the steel core would be especially bad on a thin bore, yet is it not a mono metal. So the term "Hard Bullet" should stand