Stripped down my newly acquired hi-power for the first time today (thanks mac1); a bit down on power, and a bit twangy - not so surprising for a 30 year old gun.

Figured I'd share some observations;

27.5mm bore, 80mm stroke, o-ring head. Makes 12 Fp easy

Piston is just 205 grams, which is probably why they shoot quite nicely. In another format (e.g. break barrel) with less lost volume, that could be quite bouncy in 27.5mm, but with the lost volume of a tap, it balances very nicely (well certainly in .22)

Rear guide fixed to block a la FWB sport.. great for stability, annoying for spring choice.

Replaced the spring with one which was a decent fit on the guide (unlike the original), then made up another piston sleave (it has what looks like a factory sleave already) as the piston-spring clearance was way too big. Slopped on some moly grease and zero twang

Decent ABT mechanism (if you let slip which cocking), although not needed with a tap whilst loading. In fact on the first diesel shot post rebuild, the ABT actually trapped the piston back about 1" on it's bounce cycle - which gives me an idea

Piston piston head o-ring was a little loose so replaced with fraction larger, but I think this is just down to wear. 3mm CS.

Trigger is basic but functional. Seems to be single stage.

On the chrono it likes LRGs and superdomes, hates accys.


All in all quite decent really, shoots nicely; I may look for a wooden stocked one.