If the primer looks normal, I'd polish the pin and pin housing, you have to disassemble the trigger and hammer group to get at it tho, the top pin locks the firing pin in position, but when the hammer is back, the transfer barrel is in the way, so unless the t-bar flops back because it's worn, you have to tear it all apart to remove the pin, I use numbered drill bits and flitz by hand to polish both the small and large part of the pin housing.
Tim