I have seen in the past with 7.62X39 that Remington cases have small primer pockets and most all others have large primer pockets. They were the only cases like that I have run into until now. I was working some of my once fired 6.5 Creedmoor cases from the past few range outings and I noticed that the Federal, FC head stamps have small primer pockets. So now I'll have to go tomorrow and get a block of SRP's for them. I have about 50 or so that I bought for the few Remington 7.62X39's I have. Learn something new every day.