FOR THE RECORD....Small Block Chevrolet Valve Stem seal O ring's are a PERFECT fit for the Breech seal on these rifles... Two superglued together on top each other are a good perfect fit. designed to withstand oil, heat and friction inside an engine... its gotten me through in a bind.can get a pack of 16 at ANY auto parts store for about 2.96... (look for say a 85 Chevy truck 350 Valve Stem seals (o ring type)