Osprey rebuild/tune-up, any tips?

[evert]

Theras an old Osprey in my Collection of vintage British springers, in need of some service

Its missing the loading tap, and was sprung with a square section spring that seems to have ovaled the sear pin holes and the holes in the cocking arm. Not very bad, so the gun will be made into a shooter.. Then I can leave the other, close to mint Osprey untouched

I have previously had very good results with Jim Maccaris HW50/99 spring in the Tracker, so I'm probably covered there, unless someone has a good tip on alternative springs?

Are there anyone here who have experience with seals- what should I use? Replace the piston rings with o-rings, as I see some of you have done, or machine the piston for a HW30 seal?

And then theres the tap, and tap fitting... I see there are conical and cylindrical taps, so I'll have to measure it and see what I have. When fitting taps, is it best to lap them in with abrasive compound, or to fit them with emery paper("only the bright spots") or are there other ways?

Anyone have any tips on where I can get a new loading tap?

Loads of questions, I'll be grateful for constructive and informative answers

[mallyally]

John Knibbs have the loading tap in stock @ £30

[evert]

Thanks, that might be the way to go if I find it to be a conical one, I'm still not home with my tools.

Does anyone have any experience in fitting these taps?

[torrens]

Hi evert,
I machined the piston down on one of my Ospreys and fitted a HW30 seal. The problem was the end of the cylinder must have had some machining marks or scratches. It shot well at first but eventually power dropped as the seal got damaged. My solution was fit a good old fashioned leather washer and it shoots very nicely.
The other one was rebuilt with new Webley synthetic rings, shot great for two years, noticeably quiet and accurate. Eventually these wore and the rifle got mechanically noisy, still accurate. My solution was keep one original ring in the rear slot and an "o" ring on the front; better but not as quiet as the proper set- up.
If the "o" ring eventually wears out I'll probably retro- fit another leather washer, it's now got a Beeman peep sight instead of a 'scope so just for fun target plinking at 20 or 30 metres.

Good luck with your rebuild
torrens

[evert]

Thanks! I dont have any synthetic piston rings, only the original bronze ring.

Will try to machine a delrin bearing ring for the rear groove, and find a o-ring that fits in the front grove, it sounds like a very good way to go, without permanent modifications!

[evert]

Took the parallell tap out of my problem-tracker(there are a few trackers in the Family too), and it fit quite good.
Running a tracker piston with a fit and sized 25mm diana-seal, the gun is running at 8.5fpe with Maccaris HW50/99 spring.

I have some observations:
-the "ledge" that the pellt skirt seals against in these taps, is a bit further down than necessary-probably crates more lost volume in compression than what is good.
-the transfer port looks a bit on the large side- has anyone ever measured the Osprey and tracker ports?