Last week when I installed a match trigger kit in my USP40 I screwed out the trigger stop screw so it allowed dry firing and a bit more. It dry fired consistently but when I finally got out to actually shoot it the hammer would not fall in single action after the first 8 or 9 shots. Not knowing where else to look I thought of the trigger stop first. Unfortunately I did not have the allen wrench to adjust it with me. I brought the pistol home and adjusted the screw for more travel and yesterday I took it out to fire it. I shot 45 rounds with no issues, so dry firing is just a start point in the adjustment process. The screw is very snug in the trigger so I don't think it was a matter of the screw turning on its own. Too close is bad news unless the pistol is for target shooting only.