Webley Osprey

[coburn]

Decided to drag the old Osprey Supertarget out of hibernation this weekend and give it a go on the chrono. Not as easy as it sounds if like me you've got a CB625. Firstly the foresight on the Supertarget is mounted on a square section mounting which has to be removed to get the chrono to fit. Then the last 1 inch of the barrel is a much smaller diameter than the rest. It took a bit of fidling to get the chrono aligned properly.

At first I thought the results were not great anywhere from 6 to 7.8ftlbs depending upon the pellet used, dug out an old issue of AGW and on test a .22 Osprey was doing 532fps with Webley pellets, about 8.5ftlbs so I suppose mine in .177 is not doing too badly. Anybody else had any experiences with the Osprey?, also I intend to pop the spring out and have a look at it and relube. What I need to know is can you get the spring out without striping out the whole trigger unit?. I know I'll have to take the trigger and its spring out of the end plug but I dont intend to remove the piston (tap and piston seals very well) so dont want to disturb the sear and safety ratchet.

[david9d]

I have a copy of the standard Osprey handbook if you want one. It gives a good description of how to strip it, and I found it easy enough to follow. I can send as Word or PDF.

David

[david9d]

The handbook for the standard Osprey gives the power as 650ft/sec for the 0.177 and 550 ft/sec for the 0.22. What does yours give?
It also mentions a seperate handbook for the Supertarget version, so there must be differences. Could be that it was set up for international competitions, where I believe that a power of 6 ft/lbs was normal.
Copy of book sent to your email, and good luck with your project.
David

[coburn]

Mine is an early Supertarget with the std stock not the deeper more target style fitted to the later Supertargets.

Performance as follows

Milbro Caledonian Ave 658 fps. Over five shots low 600 high 696fps
Wasp (old type) Ave 633fps over 5 shots low 550 high 701fps
H&N Silouette Ave 495fps low 472 high 524fps
H&N Match Ave 627fps low 611 high 639fps
H&N FTT Ave 517 low 506 high 536

Ave ftlbs from 5.15 to 7.21ftlbs

As you can see consistancy with the first three types of pellets is bloody awful however thay are all a bit old and showing their age. The last two show much better consistancy. I thought the spring felt quite good until I tried cocking the rifle without the beartrap ratchet(held the lever in with my thumb). Spring felt it was out of an old biro pen, very weak and springy. So I may have a low powered and very worn target spring in there but I've ordered a std replacement from Chambers.

I've thought about replacing the metal/ptfe rings with O rings to improve consistancy but as I've said elsewhere the rings do appear to seal very well. Dry firing with the tap open results in no loss of air.

I don't want to up the power of the thing just get it back to what it should be. A friend of mine made that mistake years ago and sent his Osprey to a notable tuner of airguns and ended up with a rifle that was like a hand grenade looking for a war.

Oh and thanks for the info.

[T 20]

Hi Coburn

The Osprey Supertarget velocity was lower than a standard Osprey.

The Airgun book gives the velocity of 550 to 570 fps.
Ospreys and Hawks intended for the German market had the front of the piston drilled to lower the compression ratio and hence their power output.
If I remember correctly the Supertarget's power was reduced by the use of a weaker mainspring.

I always found the ptfe piston rings on my Hawk to be less than brilliant and would be constantly changing them to keep the power up.
When piston rings like these are used in Hydraulic cylinders they are normally fitted on top of a square section rubber ring to keep them in contact with the bore.
If you could fit an O ring to the piston instead of the ptfe rings I should think your consistancy would be a lot better providing the tap is a good seal.

If you wanted to go mad you could fit two O rings and use the gap inbetween as a reservoir for SM50 as Mr Bowkett used to do (I think I sent you this article by email).

All the best Mick

[coburn]

Thanks T20. I have got that article you sent me. I stripped it last night and the last coil of the spring had broken off and fell out when I removed the mainspring!.

I've got a new standard spring on order so hopefully that will cure the low power and the inconsistancy its been showing.

I remember speaking to John Knibbs some time ago and he confirmed what you say about the shorter mainspring being fitted to the Supertarget. I am also led to believe that a weaker trigger spring was fitted lightening the pull to 1.5lbs. Beeman also lists this in one of his guides.

[coburn]

Amazing what a new un broken spring can do. It was a good 1.5 inches longer so mine may have had the target spring in it.

H&N Match ave 744fps 14fps variation
H&N FTT ave 644fps 10fps variation

Thats 9 & 8ftlbs respectively, just what I'd expect of a .177 Osprey. Once again thats for the suggestions and David for the Osprey Handbook.