Another simple mod...April 15 2011 at 11:49 AM
Jim Crawford (Login BlueMeanies)
Crosman Forum Member
from IP address 126.96.36.199
I've been playing with lately.
Been messing with a HB22. Done the standard valve porting, valve spring, hammer spring stuff. I have gotten a nice 50fps bump in power. I botched the stock poppet while grinding the shaft, so I made a new one out of Delrin.
At first, I left the valve shaft length about 3/64" too long. Noticed a power drop and a noise increase. Then, I ground the shaft to stock length and got my power back. Got me thinkin'(a dangerous thing), that if I removed just a bit more that this would allow the hammer spring to unload that much more energy and thus strike the valve faster. Net result, the valve opens quicker allowing the air to hit the back of the pellet more abruptly.
Sure enough! Gained another 15~20fps by grinding the shaft length about 1/32" shorter than stock. Gun seems quieter as well.
Has anyone else experimented with this cheap 'n easy mod? Heck, didn't even need to take the valve apart to do it.
BTW... Ground a new shape on the sear and actually got a very sweet trigger pull on the Benji. I'll post about that when I have a minute...