All the Ruger revolvers I have been “involved” with have “locator pins” in the grip frame with matching holes in the grips to help keep the grips in position. This is necessary with grips only held in place by one screw, and usually does a good job. My old Herters .44, however, has very large locator “pins” – actually more like “studs” – that do not extend very deep into the grip holes, and these sometimes allow the grip to slip. I had entertained briefly the idea of adding an second screw, perhaps passing through part of the grip frame (as the one from the factory probably should have been set up), but hesitate to add another hole.
My AMT Backup .380, although a semi-auto, has only one grip screw and uses an inletted grip that snaps into the recesses in the frame to hold itself in place. This would be nice to have on revolvers, also, but would involve some “tricky” wood working to get it right. I had been thinking of another possibility, and saw a revolver done this way in a photo on www.sixguns.com – using a block fitted to the underside of the grip to hold it in position on the grip frame.
The first block I cut from a sheet of poly board I tried to match closely to the opening it would “fill” in the frame, but on the second I realized it only needed to make enough contact to hold the block in position
The grips I made for this gun now are easier to get in place, and stay there much better! I have some purpleheart wood on order to attempt another set of grips for this one that will hopefully compliment the “plum” color of the new rust brown finish on the cylinder frame.