Checking my thinking here. I am shooting a Ruger GP100 4" 357 Magnum with 158 gr Missouri Action Boolits over 5.0 gr of Unique and a Winchester Magnum Primer. This "38-ish" load I use at steel challenge. Don't need much just to ring some steel. I'm using the magnum primer as I sometimes shoot with ambient temps at or below zero degrees F. I am seeing leading at the forcing cone and in the cylinder throat. The Missouri Action boolits have and advertised BHN of 18 and measured on my Cabin Tree tester at about 20 BHN. I'm thinking this boolit is just too hard for my load and I would be better served with something in the 10 - 12 BHN range. Is my thinking correct here? Suprisingly, before these I was shooting a Meister boolit that is advertised at 16 BHN and measured about 20 BHN with no leading.