I would agree with Semisane on this one. Remington Kleenebore and Winchester 777 primers do not seat the same in my Knight Bighornor my Omega. I haveto push pretty hard with the flat end of my capper to seat them. I dont have any problems using Winchester W209's in any of my rifles. If you use 777, the crud ring will be a little worse with the W209's. I swab between shots, so this isn't an issue for me. Try seating them with your capper. That should eliminate your problem. You may need a De-capper to remove them though. My capper has both.