I have loaded just about all of my own as well as several other folks ammo for most of my life. However, my experience with the bigger case capacities that are out there nowdays are limited. For the most part past loads in belted cases have always been stoked using the Fed 215 Mag primers and I have had great success with them. I used them mostly due to pouring in what at the time was large amount of the slowest buring powders, wether it was ball or otherwise. In the past year or so here I have noted continued references to the Fed 215 but did not always "assume" it was the standard or the mag. Now however, I have been loading some of the bigger capacity cases and it has me wondering.I have also noted the use of Russian primers, not necessarily for these type cases but other loads. Are these specificly for competition, are they more consistant, or what is the reasoning behind them in general? Anyway just had some free time and since this was on my mind figured I would throw it out. Thanks for any help this way.