BSA Airsporter Mk5 internals query

[deejayuu]

Stripped today 'cos piston was seized. As expected buffer crumbled and nylon head binding badly. Seems the fix requires alloy replacement head but for the mo' going to keep as found.
Can anyone say what the steel piston ring is for? Thanks for looking.

[piggy589]

Described as a scraper ring on the big supplier's site,no need for it.

[PhatMan]

deejayuu,

The alloy head from Chambers comes with an O-ring that is far, far too big

Luckily my friend had an O-ring in his 'odds & sods' box that gave the correct fit.

The O ring position on the Chambers head seems far too far back from the nose of the head - IIRC about 15 mm - why they didn't put it just behind the nose I don't know.

Have fun & a good weekend

Best regards

Russ

[look no hands]

I've never seen a scraper ring like that before on any of the heads I've taken out but saying that I've never had one with a synthetic head either only alloy.

Pete

[jjjjjj]

I have had two bsa scorpion pistols with the same head.

[deejayuu]

Thanks all. Back together temporarily and output around 8 ft. lb. with Superdome. Original, as found, spring 3/4 tap washer buffer and near enough "O" ring from bits draw. That'll do nicely for now.
Needs a cocking lever latch. Fragile synthetic thing.