The links above show you how to do it (it can be a little tricky to explain in text) but here goes:
In the top of the body above the bolt there is a hole for a 1/8 allen key. After removing the bolt, stick the allen key in the hole and through the bolt passage into a second hole, where you will stop on the hammer. Usually you'll have to push/pull the hammer a little to find the lug in it, but once you do, make sure the allen key is set in it (should be pretty stiff). A quarter or half turn "in" or clockwise should just about fix it. You can test it by holding the trigger, pumping the gun, and paying attention to the distance between the backblock and the back of the body when the hammer drops. It should release when the backblock is roughly 1/4 to 1/8 inch from the back of the body.
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