Square Grips On A Round Frame

[Dennis The B]

I have a Model 625-9, "Mountain Gun", in .45 Colt. I've decided to change out the grips on the revolver (Hogues), and replace them with an older set of Herrett's Shooting Masters. These are the smooth ones with finger grooves.

I slightly modified, and refinished using Minwax Sedona Red stain, and several coats of Tru Oil, topped by Johnson's Paste Wax. The original grips had cut grooves in the backstrap, and lower fingers. I filed and sanded the grooves away, taking care not to go any deeper than the bottom of the grooves.

As you already know, there's a significant gap in the inside back of the grip panel. Is there a chance of damage to the grips from the gap, or am I overthinking this? Following are pictures.

 

[H Richard]

Since it sounds like you are pretty good working on the grips, I would make a filler plug to take up the space. I do think you may have an issue with the grips biting you if you don't.

 

[VM]

The void inside the grip is a non-issue.
All S&W grips are held in place on the inside by the half moon disk (washer) at the top and the butt pin at the bottom. Nothing else is needed. You will not damage anything by leaving it the way it is. S&W made a J frame target grip that is used for rd and sq butt..........there is the same void inside when used on rd butt.
Think about a magna or service stock...............same two holding points.
Oh and by the way, I love your modified grips. Nice job!