while at the range yesterday, after about 60 rounds or so, the hammer refused to fall, the trigger would not budge either, i racked the slide, chambered another round, same thing. I dropped the mag, racked the slide, and the tried it again on an empty chamber, it worked, put mag back in, racked slide, no more failures, first time this has happened. I've had some problems with the play in the Wilson grip saftey, if it drifts to the left, it feels like it gets hung up, and will not engage until it feels like it slips back in place then it will engage. This is an aftermarket grip saftey, installed by a gunsmith on a Rock Island, this is the only failure of any kind i've had in over 2000 rounds. Not sure if the grip saftey is causing this, the saftey only drifts and feels like it gets hung up when the hammer is cocked. it doesn't do it when it isn't. ???????

Sounds as if the grip safety is not fit right and is not releasing the trigger. I'd take it back to the smith who did the work and tell him to fit it properly, because he didn't the first time.

found out the problem, i had replaced the stock hammer strut with a Chip McCormick strut, and it is slightly wider than the stock strut. It caused the grip saftey to catch on it. switched it out, Problem solved.