WW BSA Airsporter / Mercury Parachute Piston seal adapter kit.

Convert your old BSA Airsporter / Mercury’s O ring piston seal to an updated parachute seal, the seal gives superior sealing in the cylinder giving better shot to shot consistency and a power increase. The new adapter is easily fitted onto the pistons stub. All that is required is a 1.5mm drill bit to drill a new hole through the piston stub.

Designed & machined by myself Welsh Willy here in the UK, I have been using one in my BSA Mercury and the results have been outstanding, I had to reduce the spring length by a coil & a half to keep power below 12ft lbs. The rifle is now easier to re-assemble with very easy cocking and smooth shooting cycle.

Kit comes with

Delrin piston head /seal adapter pre-fitted parachute seal & roll pin

This adapter kit does not fit the BSA MKI / MKII models of the Mercury / Airsporter with a leather piston seal

See pics of CHRONY readings before & after, spring had to be trimmed, fps spread in low single figures, CHRONY FI Readings using RWS Superdome 14.5 gr pellets.

Kit can be supplied with a WW spring service kit or on its own.