As mentioned, the .32 H&R has a SAAMI maximum average pressure of 21,000 CUP, which has not been updated with piezoelectric (psi) measurements. This pressure level was originally established to assure safe use in H&R guns. As a result, Federal Cartridge, Hornady and Black Hills Ammunition each offer loads that are within this pressure guideline and are suitable for use in all guns.
However, most other .32 Magnum revolvers offer notably greater strength than the H&R guns and can handle higher pressure handloads. Buffalo Bore Ammunition (BBA) lists .32 H&R Magnum loads as “Heavy +P.” However, there is no SAAMI +P pressure rating, resulting in these loads being considered “proprietary” with pressures established by the manufacturer. BBA currently lists a 100-grain JHP bullet at 1,300 fps and a 130-grain cast bullet at 1,125 fps.