WB
I'm making some cases from .348 today.
Tuesday, December 18, 2018, 08:06

The brass is thick but heavily tapered in shape and needs to be blown out a bunch. As you figured out. Don't worry too much about an uneven neck, it can be uniformly trimmed. I'm using whatever primers I have on hand, rifle or pistol, whatever. Odd ones on my bench I don't know what they are, found in the primer tray, etc. gonna use them up.

I've used fast flake shotgun powder but I like a dense ball powder. I have a jug of surplus AA #7, hate to "waste" so much but it perfectly forms a case that will be used up to 20x. Honestly you fill the case with powder and make a blank. Some guys add fillers but that is dangerous as cream-of wheat, cornmeal, under certain pressure acts as a solid and can give bad high pressure. I use tissue or Dacron just to hold powder in place and not spill it. I began with half a case full, took it out and it only went "pifffft". Added more and again "piiiffffft". Up to the neck and once more "KA-BOOM!". If you reach full capacity and it still goes "pift" the blank powder is too slow. If a case is not filled out fully, hit it again! The blanks are horrendously loud and flashy, they are to be respected! Unburned granules, flaming granules, will be shot everywhere. Don't let them hit you, the kids, your dog, hay-bales etc. Each "blank" would have propelled (10) .44 Special loads so I don't like to waste it. The powder costs about 25 cents per blank so keep that in mind.

I'll weigh my blank loads and take some pictures today. It will be fun.