I was the one that started the thread on the ARMORY years ago. The 41's will do perfectly fine for your 300 BLK cartridges. I use lots of WSR and do well with all the 223 based AR rounds. The 41's just have an anvil that has a tad more distance between it and the cup. It is essentially a CCI SR primer other than that and the CCI is GTG based on using them for about 40 years for me.
Greg
Greg
