Just to stir things up, in my brief test, I got much more penetration from a .44 Mag 300g hardcast at 1370 fps than 600g brenneke hardcast slugs in a spruce log. The brenneke stopped in a 6 in log @20 yds, the 4 .44 slugs blitzed through it. It is a limited test, but I prefer the .44 hardcast.:)