Have one installed into a Custom .20 cal Air Wolf MCT. Rebarreled at 20" with an LW. ( Started life as a .177 with the stubby barrel )
* While the board will allow POWER likely beyond what you would use in .177, it would allow use of JSB Monsters or H&N Beasts if you wanted to throw heavy stuff.
** A bit of valve / transfer work / barrel port will help you realize the potential you will have.
Low power @ 7 ft lbs ... High power with make 40 ft lb with eugin pellets ( @ 34 ft lb with JSB 13.7's )
* Stock board with same valve / transfer specs ( @ 15 ft lbs LOW @ 22 ft lbs HIGH ) Just adding the board it does the ABOVE figures.
An AWESOME conversion and well worth the money spent !!! Stock boards Hi/Low now has 12 steps of power and each level programmable too !!
Use the search ... a few excellent threads address the Heli board in detail.