Quote Originally Posted by Benelli B76 View Post
PTFE is a poor material for piston seals as it is malleable and can be squashed out of shape. Polyurethane elastomer is a far better material and the most commonly used today.

Baz
Someone had best explain the ptfe failings to my guns. I fitted the first seal to an RWS 45 in the late 80s and its worked perfectly since (as they have all done). I think it's about time they started playing up a bit
Dave