As a rule, semiauto sporters have a firing-pin
retractor spring, examples being the Remington 740/742/750 series, the Browning BAR and the Benelli R-1.
Pulling a two-position safety switch riding on the back of the steel bolt shroud to its rearward position blocks both sear movement and firing-pin
If the firing-pin
spring is weak, the firing pin can get up enough steam to strike the primer if enough force is applied to the muzzle.
When I reloaded in the conventional manner that Steve outlined, I would have two or three misfires out of 50 cartridges due to light firing-pin
The snap cap, with a resilient buffer in place of the primer, is an invaluable tool for protecting and prolonging the life of firing pins and the size and shape of firing-pin
holes in the standing breech of a SXS or O/U.