As I do with most, since I love how things work.. I pulled apart one of these Winchester 12ga blanks to see how I could go about duplicating them. It’s a 2.75” hull, with 170 grains of tightly packed black powder(I’m gonna try some with Pyrodex), topped with a 1/2” fiber wad and roll crimped. That’s it. I took pics too, for reference. Just email me. Figure someone may want this info. Good to know. These are crazy loud, and a hoot to shoot outside on the 4th of July, or any day for that matter!