Tuning Trying to get Crown MK2 shooting JSB Hades 15.89 at 750 fps

[NNMV]

Trying to get my FX crown MK2 with a 500 mm barrel in 22 caliber to shoot right about 755 FPS. I am shooting an informal competition that requires it to be no more than 20 foot pounds of energy. According to my calculations if I use the 15.89 Hades (which I have a lot of ) and get them going around 755 FPS that will give me around 20 foot pounds of energy.

Currently I have my reg pressure at 110 bar and the power wheel minimum. I am getting about 600 ft./s. And if I turn the power wheel up to medium I get around 850 ft./s (too fast). My main question is should I turn the regulator up and keep the wheel set a minimum or turn the regular down and turn the power wheel to medium?  
Thanks. 

 

[Scotty1]

Have you tried using medium or low on the transfer port?

 

[NNMV]

I incorrectly said minimum in my post. But yes. I have tried the wheel at low and it’s going too slow and the wheel at medium is going too fast.

 

[Bobbybeef]

I shoot field target and the only problem you may have when lowering it is accuracy my hade like it about 900 fps when I go lower the accuracy goes to poop

 

[Sqwirl57]

Have you touched the hammer spring tension at all? Tuning that gun is going to be a fine line between regulator pressure and hammer spring adjustment. I'd start with the transfer port wheel on medium, regulator pressure about where you're at, and back the hammer spring adjustments out slowly. Take a few shots over a chrono in between adjustment to see where you're at. Once you are at your desired velocity, start grouping for accuracy. Make small adjustments to reg pressure and hammer spring until you're one ragged hole.

 

[Scotty1]

The power wheel is for the hammer setting, the transfer port wheel is a separate control. Forgive me if this is obvious, but it’s hard to know which one, or both, that you are trying. I’d imagine some combo of the two would get you close. 

 

[douger]

HAMMER AND TRANFER PORT SHOULD DI IT

 

[elh0102]

I would try to find a reg set point that gives maximum velocity of around 780 or so, and then back off the HST to get your desired 755. That kind of balance should yield the highest shot count and the least noise. Your current set point is higher than necessary.