Check your reloading manual, as many have a listing for .44 Magnum rifle, in the rifle section, as well as .44 Magnum handgun data. I have a 20" Puma that I shoot a few "upper" Magnum loads with lead bullets in it. I don't have a chrony so I cannot give the exact velocities, but I'm getting around 1500 fps with plain based, wheel weight alloy, air cooled, 240+ gr. RNFP bullets and no leading. The key is they fit the groove diameter (SAAMI states .431" groove diameter for .44 Magnum rifles). I'm not a great shot but I can keep all shots in a 4" circle @ 50 yards with the above load...