Lately I've been using up some leftover powder and encountered some interesting leading. The bullets I'm using have a hardness of 12 brinnell, and my loads are around 800 fps in a 45 ACP. In a Colt barrel I'm getting leading in the first half inch in front of the chamber. In a Kart barrel, the leading extends all of the way down the barrel. I'm surprised that the lead residue patterns are that different. Have any of you experienced this before.