Black Powder 12ga Blanks

[218bee]

Thought Id post this here instead of shotgun section.
Ive loaded 12 shotshells before using 2f black about 75-80grs and 1oz of shot and they worked quite well. A buddy of mine who knows I dabble in black powder wants me to make up some black powder 12 ga blanks for a salute cannon.
I figured ok no problem I'll just load up 80grs or so and use COW or something to fill shell to top for a nice crimp.
Havent tried yet and figured I'd ask here if anyone has done such and if Im on right track or is there some caveat Im not aware of.
So does 80grs and COW filler sound about right or should I try something else?
Anyone try this? Appreciate comments.....Thanks

[Mooseman]

I use 70 to 80 gr. of BP and a newspaper wad in mine, then a cardboard disk over the top just inside the case mouth and sealed with red fingernail polish.
Loud as all get out !

[218bee]

thanks moose

[smkummer]

Original winchester 10 gauge blanks were 8 drams of powder ( 1/2 oz.!) and 12 gauge were 6 drams of powder. The 10 gauge had a thin over powder wad and (2) 3/8 in wads which take all the room in the cartridge. So you would want to use about the same wad column in a 12 gauge to help it make some pressure. The 10 gauge winchester signal cannon really makes a boom that echos all through the valley. To save powder, one can easily use 1/2 the charge with still making a big boom.