Daryl-

It's always good to see what you have to say on these nice old bore rifles.

David, Daryl is a great resource for shooting/loading for blackpowder guns (and much more!) and he shoots/competes/hunts with big bore roundball rifles, he definitely walks the talk.

I shoot *only* black powder in my bore rifles. It's what they were made for, it's what gets the best performance out of them, and with proper loading, wadding material, and lubrication, you do not need to swab between each shot.

I have experimented with numerous different types of blackpowder patch and wad lube, and have found quite a few different products and recipes that leave the residue moist and soft, perfect prep for a second shot.

Also, real blackpowder residue is very easy to clean, no special chemicals are needed, water is all you need to get the bores clean. From there oil the bores to preserve them as you do with your other firearms and store in a safe place till it's time to shoot again - then clean the oil from the bores, swab them with a patch lubed with your blackpowder lube before you go hunting, and it's ready for action again.

Another pitch for the use of blackpowder in this particular rifle is around the issue of regulation.
As you probably know, double rifles are sensitive to load weight and velocity, as well as internal ballistics - the way the propellant burns.
This rifle was regulated to shoot a load that'll weigh a lot more than a smokeless load.
The blackpowder, cards, wads, lube, and roundball together will weigh a lot more than the lightweight smokeless charge and associated wad column.
As Daryl noted, velocities will also likely differ, and while working in load development, pressures can spike quickly when dealing with smokeless powders. A little mistake can cost yoo at the very least your barrels, possibly your hands, eyes, or even much worse.
Those are damascus barrels, beautiful ones.
It'd be a shame to ring, bulge, or blow them.
Further, that rifle will only show it's true character when it's burning charcoal.

--Tinker