McMaster-carr This might help
Double seal Viton o-rings
TheseVitono-rings resist oil and some chemicals and can be used in place of standard o-rings. They have four sealing surfaces for twice the sealing protection.Also known as Quattro seals.double seal o-rings are symmetrically designed for sealing on the ID,OD top and bottom.this designreducesthe amount of force needed to createa positive seal,increasingseal life.
Durometer hardness is A75. Temp range-15 to +400 deg.
Price depending on size (most $.50)

tell us where to buy them and post a link it would be greatly appreciated by many and if not by a lot by ME

warren

and remember "it's 30% the gun and 70% the shooter"

In some post they talked obout seal being a o-ring looking at johns post i see thats its not.
Two weeks ago in a post i said i thought 3000psi diaphragm rubber might work. Seeing Johns post i no it will, its made to compress and spring back under 3000
psi. The one im going to put in mine i will make from this. Warren if you dont get yours the way you want it ill make one for you no charge if you like.
Will pull mine out and get id and od size unless John has it all. Thanks again John.
Ray

The only rifles that I,ve seen use o-rings are the break barrels.The 48,52,54 all have a configuration similar to the 460.I,d pull mine out again to give you the exact measurements but I,m afraid to keep pulling my seal out.If you are to make some I,d make it slightly thicker than stock so it can get smashed down for a good seal.You might really be on to something there.I,d definately be interested in one also.

good idea, but where can I purchased them. Do you have a link and exact size?

Joe

John would be glad to send you some. It comes in sheet form, thats why i wanted thickness of your washer. total= seal and washer .133. i will order 1/8"
.125 hope its a little over. also order 3/16. should be able to use gasket punch on id and od.
will order monday.
Ray