I have a 12 Ga. Holland cased with all accessories, in 3.25 Nitro Magnum. The rifle formerly belonged to C.A. Walker of the Irish Guards and he must have been a large fellow as it has a 15" length of pull, with a straight stock over a checkered butt. No butt plate or recoil pad. Total weight of the rifle is 8 lbs. and with a 3" Remington Mag shell it kicks like the devil. I want to hand load for it and have been able to obtain some 2.5" brass shells with boxer primer designed for large pistol primers. I have the original Fosberry Mold with the rifle that throws a 476 Gr Linotype cast bullet. The rifle by the way is a "best Grade" sidelock in 100% condition and probably hasn't been fired more then a dozen times in its life. I am concerned about the powder to use for the load because Unique may be too fast a burn rate and 4198 and 3031 would fill the case to a greater degree and perhaps give better combustion. I am also concerned about using a 2.5" brass case in a 3.25" chamber and whether that will cause a problem. On some of the other double rifles that I have I use dacron as a filler for my 500-450 #1 and my .577's but I would think that a card wad and or felt wad would be a better container for the Paradox. Does anyone have any suggestions? Any help that you can offer would be deeply appreciated.