Hi Bob, I have on occasion, when the grips are original, but a little loose, I try to shim them up a little! Here's what I do.
I cut some brown paper from a paper bag, grocery bag, or any brown paper you can find. I then stain the strips with brown leather die, but you could even use magic marker, just make them brown. Then you have to saturate the strips with superglue. Then, cutting the strips to fit, I super glue them to whatever area that needs shimming. Trim the excess with a razor knife. repeat as necesary to build up the voids and gaps... You'll find that very little, and very small pieces are needed for success.. Let me know how you turn out.. Best, til....lat'r....GT
