I finally found some Duco locally and was pleasantly surprised to find that it now comes in a handy bottle rather than a tube.
I mixed some ~50-50 with acetone in a shot glass to experiment with my split up bamboo chopstick to make some stick-quills. They work good, and you can split them into whatever thickness/length required...
This one is from dipping, rolling and drying three times, with a final 'sealing' dip. I wanted to see how durable it was with a lot of powder on it. Turned out to be very sturdy...
When I was done playing with my pixi-stix I thought what the hey, let's see what happens if I dump the remaining powder into the rest of the solution, scoop it out and let it harden. I've invented the blackpowder cow pie (patent pending)
It's pretty hard stuff. I broke it up and lit small pieces to compare how it burns with similar size piles of powder. Seems to burn about the same, and the chunks leave less residue on concrete than a pile does (possibly because much of it is suspended above the concrete).
Anyway, I'm thinking it might be possible to make up "caseless cartriges" for cannons using a simple teflon mould (?)