With the .22 16" theoben barrel I am getting ragged hole 5 shot groups at 50 yds with my MkII
Had the gun set at 28ftlb initially but found I was wasting air and was causing a tad too much muzzle lift with the jetting. Took it back to 26ftlb which is much more quite and less wasteful. I have nearly 100 shots out of a fill.
Plenty of energy left at 60 yds to kill rabbits with provided you are accurate enough.
Am about to try a 20" BSA barrel on the gun which I have been assured will tighten up the groups even further. Which will be nice