Here is my B3-1 before and after rebuild/refinish, I bought this rifle off of eBay for $10.00, shipping was another $10.00
Robert, Archer has the leather seals right now, 3 pack $23.99. Order some before he runs our again.I don't believe these old Chinese guns were intended to re-build or replace parts. Shoot'em till they quit and toss'em.The plastic seal you have that came with the kit is made to snap over then end of a piston machined just for it. Older guns came with a leather seal that screwed on with a plastic disk under it. In between they came with a metal disk that screwed on and the plastic seal snapped over the disk. I've seen and used them all. The only way to get a screw on metal disk is off an old gun.