Only 4 months old send it back to AA let them sort it.

Yes i did the same with my pro sport, timbum kit very good fitting spring guide no pre load washers and shoots 11.4. getting rid of the heavy piston weight makes it better imo.Worth the £23.

What does it shoot likenow?. I stripped mine down relubed with cv joint grease polished the spring ends and fitted a tin bum top hat and spring guide kit, all easy to do your self. It now shoots 11.4 with aa feilds (with no preload washers). All well worth doing.

I like that is it aslip on? hoiw much longer does it make the prosport?.

Never owned a s200 do the mags self index?.

The o ring slides over the cocking arm if i remember right there is a groove for it to sit in .

Got a swift stumpy on my r10 60mm shorter than a hw and very quite £40 .

When i had my tx i used a o ring simple

I got a no8 compete with a leather case with belt loop about 20 quid . great knives.

As above just serviced mine with AA parts spring piston seal etc then fitted tinbum top hat and spring guide. No power washers and it is doing 11.3 and is as accurate as my r10.Love mine to bits. Had a tx hc and i prefer the prosport atb andy