Hammer Spring Adjustment

There is probably a lock/grub screw tightened against the hammer adjustment screw. You will have to remove the two small allen head screws that hold the hammer adjustment screw assembly and remove it from the gun. Loosen the grub screw, make your adjustment and tighten the grub screw, reassemble.

I have the Brocock Sniper Magnum and that is how mine is, aside from the flathead screw to adjust...mine is an allen head.
 
Well that is normal...when the grub screw is tightened, it is tightened against the threads of the hammer spring screw. This will flatten the threads slightly on the hammer spring adjusting screw and it will not turn easily...it will turn with some effort...you may have to turn back and forth to "clean" up the threads to get it to turn easier. I would put some oil or a little dab of grease on the threads of the hammer spring adjust screw to help it move freely. wipe off any excess when your done.