Diana 25 .177" velocity

[Kitcarguy]

One of my books quotes 525 feet /sec for .177, 390 for .22.

[Geezer]

One of my books quotes 525 feet /sec for .177, 390 for .22.

That sounds about right.

The 24 (Webley Air Wolf) was listed by Webley as making 575 in .177" and 495 in .22".

[Drew451]

I was surprised to discover my '90 24 giving around 640 fps with 8.2 gr pellets, which is weĺl over the figures quoted in Walters The Airgun Book. Im almost certain that the 25 has a greater stroke but a lighter piston and I would expect a good example to comfortably exceed 550fps.

[evert]

Thanks for all your replies!
I found the 525fps and 390fps velocities in the Blue book last night, but previous experience tells me the Blue book cannot always be trusted.

Anyway, this all means the D25 needs a new spring, as its leather seal is in good condition.

[evert]

Just put in a Maccari HW30 spring, which is said to be good for these guns. Added a delrin tophat that gives about 3mm preload.
After a dozen shots to burn up some excess neatsfoot oil, three 7.33grs JSBs clocked in at 584-587-586fps. The rifle proves to be very easy to shoot accurately too, with three shots at ten meters touching. I am more than happy with how this turned out!

[Drew451]

Sounds like a very worthwhile project, well done. Sweet and accurate guns, the small Dianas. RWS Meisterkulgen may be worth a try in your 25. Usually work better than most, and of course, make nice clean holes in paper.