I shoot 90 grns of black powder in my 50 cal flintlock and it is not too much, it is just right. It is not necessary to swab between shots either. I used to take my flintlock to youth conservation camp annually and teach the kids how to shoot flintlocks along with another guy. We loaded down to 70 grains for the kids and i really made little difference in accuracy and we would have as many as 6 different kiids shooting before we ran a swab through the barrel. Muzzlel loaders are not a one size fits all, you must find what the rifle likes and stick with it, there are no absolutes.