I have loaded a lot of black powder cases, but am having trouble bulging the cases at the bottom when seating the bullet. The only round I am having trouble with is 38 Long Colt. On a 158gr. bullet I measured from the crimping groove to the base of the bullet and added powder 1/16" to 1/8" more powder and they are balloon head cases, and should have room, but when I seat the bullet it bulges at the bottom of the case enough that it will not chamber. I went from 18grs. down to 17grs, and don't want to go down anymore for fear of leaving a space between the bullet and powder. Any thoughts?
Thanks
Reno