if it is anything like most other ruger guns it has a magazine disconnect safety that locks up the pistol if a mag is not properly inserted, try slapping the bottom of the mag after inserting to make sure that it is properly in place. also try taking it apart and cleaning extra well with brake cleaner to ensure all of the packing grease has been removed and relube it with break free CLP with special attention to the slide where it contacts the frame.
ignore my complete lack of capitalization. I still have no problem correcting your grammar.
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