A lot of gunsmiths will balk at re-chambering anything to a more powerful cartridge than originally built for. With the amount of steel in a k frame cylinder, I can not believe that having the chambers cut so 32 H&R Mag will fit could possibly cause a problem in the "pre model 16" other than the damage to the collector value. I am not up on what the chamber pressures are on the new 327 Magnum, but my guess is that wouldn't cause a problem either. Then you could shoot any ammo you could find (327 Magnum, 32 H&R Magnum, 32 Smith & Wesson Long, 32 Colt New Police, 32 S&W, 32 ACP). I have probably shot more 32 ACP out of my 32 S&W Long revolvers just because it was the cheapest and easiest to find. They get the chambers pretty dirty so you need to clean them very well before you shoot Longs, but other than that, they work fine since they are acutally semi-rimmed.