I'm going to work up some new loads for my 50BMG. I will use IMI brass for most of my reloading but I also have some Igman and CBC brass. I'm considering working up the loads with the IMI brass and when I find my max. load I will use this load as a pressure reference in Quickload. I will then change the case capacity in QL to that of the other brass and adjust the charge weight until I get the same pressure as with my reference load. Will this be a safe practice or do I have to work up the loads with the other brass as well?