The .327 Federal Magnum is rated for 45,000 psi, the H&R Magnum is only rated for 21,000 psi. Most modern .32 H&R Magnum revolvers can handle at least 25,000 psi which is a good middle ground for a Self Defense gun. The max power .327 Fed Mag is a flame belching, concussive bomb out of anything under 5". If you download to something with low recoil but still able to do the job, you get a large Extreme Spread (ES). The .32 H&R Mag, on the other hand will get consistent low ES and better accuracy, low flash and if you keep it subsonic, not that loud and no concussion inside a house/building/structure. Even in my 5.5" barrel Ruger Single Seven, I usually shoot .32 H&R Mag, just because I don't always like to shoot the fire breathing hyper sonic dragon.