@STO, yes, definitely... On mine, when switching from .177/.22 to .25/.30 gets me around 30 to 35 FPS everything else being equal.
One thing to realize is that this platform is capable of shooing up to 78 FPE with the 600mm barrel. Same valve, same action, same transfer port. The only difference is the barrel port/probe port for each of the calibers. For .22, the probe port is about as large as it can get, although I have seen some where the probe port was enlarged (on a Wildcat .22). So it stands to reason that if the gun as a whole is capable of 78 FPE in .30 caliber, getting the .22 to shoot 42 to 45 FPE wouldn't be asking too much. I have a B liner on back order at AOA to do just that to shoot the .22 RD Monster 25.4 grain at around 875 to 880 FPS. I think that's about as fast as it'll be capable of doing with the 500mm barrel (Ernest told me that). Heck, if the RW .22 can shoot over 50 FPE, why not the Crown with a longer (600mm?) barrel.?