RE: 44mag / 454 casull
It is important to have all your cases the exact same length so you only have to adjust your crimping die one time during a reloading session. Yes, you CAN shoot black powder in either the .44 Mag. or .454 Casull. IF you don't mind cleaning ALL the BP crud out of your gun after shooting, and likewise don't mind scrubbing the fouling out of each fired case, assuming you plan to use the case again!! I weigh each charge when using Unique, because it does not meter uniformly through my Redding powder measure. HS6, HS7, 2400, H110 and WW296 seem to meter very accurately. I do check my powder measure setting with a scale every 25 rounds to ensure the setting has not changed while throwing charges. I use the cast SWC 255-grain Keith bullet from Lyman (452424?) for my .45 Colt and .454 Casull loads. Also use the Cast Performance LBT 265-grain gas check in .452 diameter. In the .44 Mag., I use the Lyman-Keith .429421 SWC. I seat them all so the crimp is applied at the crimping groove. These bullets are generally superior to any jacketed bullet in heavy handgun loads!! RCBS dies are excellent, as are Redding and Forster. Other brands are also good, but these are the ones I have the most experience with. I have never worn out any pistol brass!!
Keep yore powder dry!!