It sounds like someone has put a CS trigger block on a .22 Barrel and cylinder.
For trigger adjustment you need to loosen the screw closest towards the stock on the left hand side of the trigger block, then adjust the corresponding screw on the left hand side of the trigger block (that is assuming it is a three hole trigger block) Once that left had screw is adjusted to give you a lighter trigger pull, re-tighten the screw on the right hand side of the trigger block as that is the locking screw.
One side of the trigger block(right I think) should say "lock" above the screw in question, and the other side(Left?) should have an 'H' and either an 'L' or 'S' (I am answering this from work without a rifle in front of me )
Hope you can make sense of this ?
ATB
Lakey