When I first got my No2 mkIV* .22 it would not extract the empty cases. After inspecting it, I found that the rim of the chamber had been peened by the firing pin; causing the case to jam on extraction. Obviously someone had been dry firing it. Fortunately the firing pin was still intact. Some careful tidying up of the chamber rim and it works a treat. Luckily the No8's bolt heads have a shoulder that prevents this problem.