Going to have to come off the sides of the rear section....the pin that the bolt hits to cock it keeps it from rotating but the front section should be left alone. I'd order a spare hammer before taking that step (they aren't expensive).
Might be several ways to knock the power down to 12 foot pounds...expect Crosman is working on that for the UK market.
Steve supplied a couple of nice charts and a picture of a radically ground on hammer. http://www.network54.com/Forum/79537/message/1214749516/You+need+either+a+%28much%29+lighter+hammer%2C+or+a+lower+fill+pressure
I decided that this rifle was going to be a hunter (gray squirrels). Not that I don't practice with it, but am content with the 26 shot "sweet spot" @ 22 foot pounds on air.
For the last few weeks have been running it as a bulk fill co2, which puts it in the 11-12 foot pound class (but a whole lot of shots).