Home made Innova piston seal

[Morningstar]

Hi Mate, Its not hard enough ! IE short life ?
Measure Cylinder bore, Get out your PTFE, Machine to size, All dimensions ! ( Making the fit into the Pump arm head, Tight, ) Drop in boiling water & Fit, Job done, Good as new, Alternately, ? Machine new pump head, with Double O ring ( ALA Crossman Pistols " Modded ) Easy fix ! Cheers,

Thanks geddfin! only trouble is, with me is access to a lathe.
I did try machining some rubber down on a pillar drill but It did'nt turn out to well if you pardon the pun. have made some of other bits for them out of 19mm brass bar using a pillar drill and files and emery paper. Stoneage I know but enjoyable.