I use 95 hardness cast polyurethane rod, only one seal needed, a very efficient and simple valve system.
Cheers, Lawrie.
Lawrie I sent you an email the other day. Did you get a chance to read it please?
Vintage Airguns Gallery
..Above link posted with permission from Gareth W-B In British slang an anorak is a person who has a very strong interest in niche subjects.