Issue with 177 cal Cricket

I got a cricket from one of my shooting buddies and I'm having a little issue. He had it tuned to 13 FPE because he used to use it for FT. I want to bump up the power to about 19 - 20 FPE to shoot 10 gr pellets around 900 fps. The hammer adjustment screw does not affect the pellet velocity. I screwed it all the way in until the gun wouldn't cock and screwed it out about 8 rotations, but pellet speed stays the same.
 
It sounds like it’s operating at the velocity plateau…meaning the valve is already being hit so forcefully that it is open all the way until the pellet leaves the muzzle. That is why adding more hammer strike does not increase the velocity.



To increase velocity, either the regulator pressure will need to be increased or the porting opened up…or both.
 
I would start by asking my shooting buddy what he changed and then change it back.

He bought it from Wildwest Airguns and had it set to 13 fpe. So he didn't do anything to it. I would think that even if the reg was lowered by WWA the hammer tension should still affect the power output.

As i said, in the box there are 2 SPRINGS, 1 short low power,1 long high power

Did you check that ?
 
Again, the fact it’s producing the same velocity at a variety of different hammer spring settings means it is operating on the plateau. It is uselessly blowing air out the end of the barrel after the pellet has departed. BTW it is not necessary to swap out the hammer spring to know this to be true.



The only other possibility was that perhaps the threads were stripped and the adjustment wasn’t actually changing the spring tension, but the fact that you were able to take it to coil bind removes that from the equation.



To increase the velocity, you will need to either increase the regulator’s setpoint or increase the porting, or both. Short of swapping parts (e.g. longer barrel), there are no other ways to do it. Note if and when you increase the regulator’s setpoint, it may then be necessary to use the stronger spring…but only if you are unable to reach a point where adding spring tension produces no further increase in velocity.
 
That’s a good plan. From there, you can calculate an approximate setpoint for the 20fpe goal based on the current 13fpe. This ratio is 13 / 20 = 0.65. So let’s say the current setpoint is 1000psi, the new setpoint would need to be somewhere in the ballpark of 1000 / 0.65 = 1540psi. Since a heavier pellet will earn more energy, something like 1450psi will probably get you there. All this assumes no change to porting.



However if there are any porting restrictions under 0.135” (approx. 75% of the caliber), you may want to consider opening them up. That will allow the use of a lower regulator setpoint which in turn will yield more shots per fill. Good luck and keep us posted!