Quote Originally Posted by T 20 View Post
As the hawk is the same bore and stroke as the Osprey the information could help you, I found a 2.5mm transfer port to work well on the Hawk.

What length is the transfer port on the Osprey as that needs taking into account when sleeving down ?

All the best Mick
Thanks Mick. The port is about 19mm. Made a brass sleeve, and it seems to be a tight 4mm, not a 4.1mm.
The sleeve is 2.5 mm, and the gun has calmed down, but its still not giving me the wanted velocity- Im getting a max of 510fps with 14.5grs pellets no matter what seals or pistons I use(have three different pisons and have tried several sealing options).

I think the next place to focus might be the tap- its from a tracker that has given me a lot of headache, so I'll need to get a couple new taps and tri fitting one really tight.