I don't know if there is enough thickness in these grips but on my M39-2 in 9X21 and a 1911A1... I relieved the underside of the grip panels (with a mill) and used skateboard tape on the front strap. Trimmed to fit under the grip panels edge. (Also a couple of other mongrel 22 pocket pistols I did both front & back straps.)

My old service M66-1 still wears Hogue nylon (not rubber) monogrips... there is something sophisticated about the shape. With factory service stocks, the drill was fire 2 (full house magnums) & adjust grip on the gun. With the ugly monogrip, I could rip through all 6 & have a better grip after than when i started. I don't know if there is any such for the 3913... besides it's probably a individual hand fit thing.

Best wishes.

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Reserve Officer 9yrs