I have a problem with my FN-49 occasionally slamfiring, about once every 20-25 rounds. This can be caused by a broken one-piece firing pin which is floating. I however have a two-piece firing pin which is supposed to prevent this. It has been suggested that commercial primers are too soft and may be detonated by a floating firing pin. I reload my own ammo, so I am wondering what primers might be available besides the Federal and Winchester primers I have been using. Or if there may be some other cause?