I tried using these ones from Knibbs but they kept disintegrating,
https://www.airgunspares.com/23cwebl...reechseal.html
so I ended up using a yellow P.U one from T.R Robb which works very well although it’s a shame it is bright yellow. I wanted it to be a good shooter.
https://www.trrobb.com/Webley_Servic...8_9413797.aspx
Cheers,
Matt