Curious to know how the cases were re-primed. I, too, would advise to stick with BP. The Navy Arms ammo put out a few years ago were, IMO (after chronographing against some earlier Remington ammo), too hot for use in the Rem O/U Double-Dee's! If the gun used in the demonstration had a "reinforced" hinge, it is a late Fourth Model. One must carefully check the hinges for cracks, especially on the left hinge, where it is counterbored for the screw head. The "reinforced" hinges are simply NOT undercut. These are the so-called "monobloc" hinges. The cracks are almost always the result of flipping the barrels back hard when opening them. See "Dr. William H. Elliot's Remington Double Deringer" by Drummond, Johnson, Williams & Barnard. Be interesting to know the stamping on the top of the barrels. Probably "REMINGTON ARMS - U.M.C.CO.ILION,N.Y."