Quote Originally Posted by tinbum View Post
Depends on the gun. The 25mm piston 77’s seemed to benefit from opening to 3.9mm, modern LGU/LGV were similar. How much air are you shifting and what is the current volume of the TP?
A simple spring gun they say

My Cometa 300 compact.22 has a TP of 4.00mm x 12mm
The .177 fusion has a TP 3.25 x 12
The 220 compact.22 TP 3.00 x12

All share bore size but strokes a little shorter on the 300-220

I want to fit a full length .25 barrel to the 220 and hopefully find a TP that allows a barrel change without any internal changes

I now see Cometa change their TP’s to suit what cal/barrel is being fitted

My 300 and 220 share the same bore, stroke and calibre.
The pistons are different and the 300 makes 10.8 and the 220 10.2, the 220 feels nicer to shoot and has become my go to gun, but at the range at 30yds both make the same 20p holes with 10 shots, the 300 definitely has a snap to it and feels lively compared, and I never thought it would be as accurate.

Ive now added a 7mm SS nose with a hwBritseal and dropped the power to 10 and it feels nicer in the shoulder. I can feel how much quicker the 300 is but another range visit to see if accuracy has changed is needed