Originally Posted by
45flint
How long have they been available in airguns?
Interesting point. When I started work in polyurethanes in 1994 we were already using additives. There are two types of urethane, polyester and polyether. I think the polyester is more susceptible to bacteria attack. I have Weihrauch seals out of rifles over 20 years old and they are fully functional in good condition. It is difficult to know what material each manufacturer is using without asking for specs. I would think that all manufacturers use modified resistant polymers now.
Baz
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