Tuning JSAR Balanced Valves

Don Cothran does know how to make a valve. I was getting around 42fpe at 239fps from my arrowgun with a highly modded valve. Then I added his valve did some porting and raised the psi a bit and ended up at 137fpe at 432fps with the same arrow. The better part of this increase was due to his valve flowing so much more air than mine.

https://www.airgunnation.com/topic/i-built-an-arrowgun-recovered-from-the-crosman-green-forum/?referrer=1

 Edit;

https://www.gatewaytoairguns.org/GTA/index.php?topic=187034.0