my son is involved in the junior smallbore program at my local range and they've issued him a 2000L. about one out of every 4-5 shots does not fire and it appears that the firing pin is lightly striking the rim of the cartridge. I have it home now and plan to disassemble the bolt and give it a good cleaning. are there any other reasons why this gun is not consistently firing? the only other thing that the smallbore coach and i can think of would be a weak firing pin spring.