“the Meteor MkI, which has a leather piston washer with a neoprene buffer sandwiched between two steel-bearing washers situated behind”
apparently.
Thanks Geezer for posting the link to the article on the history of the Meteor Mk1 and the telescopic sights that were available for them , which in effect, started the trend for equipping air rifles with scope sights. ...fascinating stuff! 😎