Crosman 99 Velocity Question

[egillman]

I just used my new F1 chrony to check out my Crosman 99.  With 14 grain pellets, I was getting around 450 fps with the hammer at normal pullback and 500 fps with the hammer pulled all the way back.  Does anyone know if this is typical for a Model 99?  Thanks.

[egillman]

OK, so I tried a lighter valve spring in the '99.  I was able to raise the velocity on the low hammer position from 450 to 500, but with the high hammer it went no higher than 500 fps.  Seems like something else is the limiter on this model.  I also had several CO2 cartridges that exhausted their entire contents as soon as I screwed them in, indicating that the lighter valve spring was not sealing the valve.  So, I went back to the factory valve spring and all is OK.