Quote Originally Posted by 32:1 View Post
Had a little bit of progress today 😎

I fitted a 2mm oring and cut 1mm groove and was planning to modify from there but no need as we had decent fps and far better consistency than before, still feels harsh to me but some might call it fast.

I ran a test with the same piston and original spring and guide and simply fitted four different seals via a m6 thread, a few shots to settle down and then ten through chrono and took average of the same 8.44 JSB.

Hw 638
Oring 666
Cometa 650
TWChambers 680


This .177 220 has near 50mm of preload and my .22 has 15mm, the triggers are basic and this .177 is firmer and I’m guessing it’s the extra spring tension so I may drop fps down a little and see if it improves break
2 mm section o ring, would need 2.2 wide groove, depending on the amount of crush your running.
The cushion effect comes from the seal , whether it's an o ring or parachute seal, creating a cushion of air at the end of it's stroke.
Just spotted your picture on the other forum , you have too much lost volume in the Allen socket head.