Quote Originally Posted by evert View Post
That would be me.. Mine is stamped "Magnum", but it also has the F-in-pentagon German 7,5joule freimark, and a relatively soft spring, possibly meant for the restricted German market.
I have been trying several leather seals, a modern Diana 28mm seal, and have also sleeved the TP down to 3mm, all in an attempt to raise power with the original spring in the gun.
Before the TP sleeve the gun was a bit slammy, with all seals tried.

I have not been able to go get stable velocities above 670-680 fps with 7.33grs JSBs, probably due to the weak spring. As time permits I will try other springs.
Thanks for that, Evert. Your post coincidentally crossed with mine, before I could read yours. I wonder, therefore, if the word 'Magnum' was simply a term designed for the German market, where the power levels are about half the levels for the UK.

Let us know how you get on with your project!