When I shot my 637 Airweight at the range, even with range loads, I often created -- and popped -- a blister right in the crotch between my thumb and hand. I tried to use a glove with padding in that point, but it changed my grip so much that I gave up on it. Now I simply put a Johnson & Johnson knuckle bandage there. Works fine, even with ten or so Remington +p 158gr SWCHPs.
Cordially, Jack