For Mortars I weigh out the charges and put them in black 35 MM film cannisters. I get the cannisters from WalMart. A piece of masking tape on the cannister is marked with the charge size.
I use a powder measure designed for black powder and bulk measure the powder out and dump it on my scale. This measure is one of those brass tubes with a sliding plunger type measures. I use my powder trickler to bring charge up to desired weight and dump that in the film cannister.
Go to our sticky at the top of the board
Safe loads and Cannon plans... for more ideas. You will find ideas for linstocks, slow match and quick match and much more.
Go to the Sticky for
Cannons links and you will find sources for fuse and powder. For fuse I am partial to
www.cannonfuse.com because they are in Montana and came to our cannon shoot. Home town bias, I guess.
Powder inc. is a popular for powder. Their prices at first glance appear to be higher. But after you realize their price includes shipping and hazmat fee then the price isn't so bad. The other Companies don't do that and it's up to you to guess how much for hazmat and shipping. Powder Inc. will also ship to you in 5 pound lots. That's the smallest lot they can ship. I haven't looked lately, but I believed some of the other powder suppliers have followed this format now.
I do recommend you go through all the links in all the stickies above, you will find lots of good information there, provided by the good folks who frequent this board.
Don't hesitate to ask questions. Everyone here is most willing to help and share, no matter you experience or skill. Cooperation and sharing is a hallmark of this forum!
One disclaimer, how ever, should you become hooked on shooting cannons, we accept no responsibility, none! You are on your own there!