Quote Originally Posted by Mr.Fixit-Norm View Post
This afternoons fettling has now produced an air gun that cocks and shoots !

I made another top hat, this time with a 16mm long spigot instead of 5mm. The head thickness remained the same as the previous one and I cut 20mm off the rear spring guide

I decided to size the piston washer by putting the piston in the lathe and using 400 wet&dry with some light gun oil on it, not sure if that’s the right thing to do but it seems to have worked and although the piston still isn’t a ‘sliding down under gravity’ fit, it is easier to get in and out.

I also removed two of the spring washers from the trigger mech as suggested and it’s now a much lighter crisper let off

The cocking effort is still considerable, and I’m guessing the slightly tight piston and 5mm of preload isn’t helping, but I feel I’m progressing in the right direction

I put a couple of shots through using the Falcon AP pellets and then recorded 12 results on the chrono, early days I know but you need a starting point !

It was originally shooting around 10.8 - 11ftlbs ‘Dry’ with a few FAP’s I put through and I’m guessing the new tighter piston is reducing the power a little bit.
Am I right in thinking the power will go up a bit when the new piston seal wears in ? If so I might remove a coil from the spring to make cocking easier now, even after a dozen shots my elbows feeling it

Norm

594 - 10.5
601 - 10.7
592 - 10.5
595 - 10.5
601 - 10.7
592 - 10.5
583 - 10.1
580 - 10.1
592 - 10.4
583 - 10.1
587 - 10.2
591 - 10.4
588 - 10.3
The numbers look normal for a compact.
The full fat Express easily makes higher numbers.
It all depends what you want out of your springer
Pays yer money and takes yer choice