Hey guys I bought a bunch of Federal 215 primers a while ago to begin reloading the 338 lapua and just found out there is a match version the GM215M. I'm so pissed I didn't know about these. Anyways wondering what your guys experience is with both of these primers. Should I sell the 215 and just start out with the 215M primers? My whole deal is to make a really accurate load but if I can get more accuracy with the 215M I'd rather go with those. Thanks for your input.