You could ream a K frame of even a J frame 32 S&W to 32 H&R. But, if I ever come across a pre 16-4 K32 I will leave it alone, even a shooter grade one. It would have to be in pretty bad shape before I would modify it and I am not bashful about modifying S&W revolvers. I already have a 16-4 myself, but I bet even a 80 some percent earlier K32 would sell for the price of a nice 16-4 and they usually sell for well over $1000