I got some sample packs of gas checks from Vulcan. I sized 30-30 and 45-70 bullets today and so used the sample packs. So some will have gas checks and some not. Will then powder coat them. I will see how they shoot I guess. Gas checks add a few cents to each bullet. Do you use them or not? Not much of an investment with the 45-70 I guess. Also copper vs. aluminum - which do you like and why?