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kanyon · Silver Status Member

Hi..
I have a couple of questions...

Q1....what are the volumes of a Crosman 22xx & boss valve....CCs.

Q2....At what point dose the air exspantion no longer become benifical.
IE....50%....75% of total exspantion..

Thanks
Pete

AirGunEric · Site Admin

I believe Bob (Rsterne) knows the valve volumes, and the air expansion issue is dependent on the bore and barrel length being used (i.e. the amount of space the air will fill once out of the valve).

rsterne · Moderator

A stock 22XX (or Disco) valve is about 2cc internal volume.... a Boss Max-Flow valve is about 3cc.... The max-flow is not only larger ID, but is bored deeper and consequently the valve stem sticks out the back further.... This reduces the hammer fall distance, and can limit the power in HPA applications (it was intended for CO2).... You can get back to normal by shortening the end of the valve stem by 1/16"....

I don't understand your question about air expansion.... If you are talking about the effect of barrel length.... that will depend on the pressure.... In .177, with CO2, the optimum is about 18" give or take.... In .22 cal, even on CO2, a 24" barrel is better.... On HPA (or with a pumper at high pressures) it seems the longer the better....

Easing the flow on the inlet side of the valve.... and having enough volume there to keep the AVERAGE pressure high during the shot cycle.... will increase velocity when you are pushing the limits....

Bob