Webley Osprey ST weird flyers

[hwtyger]

Tap doesnt touch the stock afaik.
Yeah, thought about different pellets. Only use JSBscause they do well in 95% of the guns, incl this one but never tested other pellets.
Its also easiest to remember if you use same pellet in all these
Maybe 4.51 is too small a headsize aswell? I started with this headsize cause my Diana 31 Pro prefers it. Actually never looked back. But most seem to use 4.52 or 4.53

[Dutch]

Interesting case indeed.The fact that it gets more consistent after warm up is quite a puzzle, sounds like a diesel engine . The type of grease used could also be a factor (more fluid when warmer or stirred). With a bit of structured analysis you could eliminate the factors involved (human, pellet, mechanism, grease) step by step. Strap the gun down and take the shots through chrono. Round two (after cooling down) Inspect the pellets & clean barrel before taking the shots. Still no consistency from the start, open it up clean the seal, relube, degrease inside of the tube & smooth up with wire wool, check for inconsistencies. Most likely suspect I can think of is indeed the warming of the piston seal and its interaction with the grease & inconsistencies in the tube. Maybe in combination it behaves in this fashion.

[bill57]

The piston seal in an Osprey is a set of dual piston rings, much like a car engine. They were used in the Hawk as well, as Webley's first move away from leather washers. I've never warmed to them and do away with them, but if they're in good condition and working properly then consistency is meant to be their main strength. An unlikely area for fluctuation, I would have thought?

[hwtyger]

Im not sure it still has its original pistonseal construction.
As it has been serviced and tuned for close range targetwork. (low recoil, shootability)
But if it dóes have the twinring assy, than yr right and that shouldnt be an issue.
I doubt there are 'bigbore'sizes available for it like in cars that would make an incorrect size possible.

[hwtyger]

Im very pleased to inform you that the problem probably is my own sorry ass
I tried it “ semi rested” just now ( very primitive; rested on a basket with on top of that a pack of target cards its all I have; I never shoot rested.
Anyway even with this primitive hold ( couldnt hold the gun as still as I wanted) the shots still were touching or overlapping so no 1-2 cm weird flyers.
After few shots I found a more stable position and groups really started to tighten up.
Tried 4.52 instead of 4.51 but group only opened up. So that sure wasnt an improvement.
Than tried ( very old batch of) FTT which gave very promising very accurate results.
I remember my FAC Tomahawk kept giving flyers with jsb. It didnt like ftt or baracuda so I thought that was the best I could get out of it. Until I tried jsb heavy and flyers were gone.
So maybe pellets are párt of the issue.
Ill do some further testing.
Tap is tight barrel is too. Only thing that has some play is the frontsight holder. But as seen today it can perfectly shoot 3 pellets into a hole size of a 5.5mm so dont think that has much effect.
Wouldnt know how to solve it anyway; bolt is already loctited afaik