I've bought and loaded and fired thousands of .32-20 bullets - 115gr LRNFP - .312" - in .32 H&RM cases. Fun plinker at 800 fps.
Additionally, I have done horrible things to several hundred brand new .32-20 cases - take .010" off the rim thickness, .024" off the rim OD, and size them in a carbide M1 Carbine sizer, before loading 100gr DEWC (.312") over a small amount of powder for my 1895 Nagants. Fun... anal, but fun. The cases fall out of the Nagant chambers. Nothing at all to do with a .327 Magnum... I just can't sleep!
Stainz