For anyone interested, I posted this question on another board and received this well written article. This article is getting me to seriously consider the blackpowder idea.
I shoot nothing but Black Powder in all my 45 Colt and 44-40 loads for Cowboy Action Shooting, and 45-70 for long range with my Sharps. 44Mag is no different. Louis2dogs has told you correctly. Put in enough powder so that when you seat your bullet the powder is compressed between 1/16"-1/8". Leave absolutely no air space in the case, be sure to seat the bullet fully on the powder. Leaving air can create dangerous pressures, possibly ringing your chambers. Black Powder is very different in this respect from Smokeless. Those 45-70 Govt loads with only 55 grains of powder in them were light loads for the cavalry's Trapdoor Carbines. The extra space in them from the lighter powder load was taken up with fiber wads. Same with the 45 Colt rounds that were stepped down from 40 to 30 grains. You must not leave air space in a Black Powder cartridge.
But you'll have to do something about the lube on your bullets. Modern Smokeless lubes only lubricate the bullet on its way down the bore. Black Powder fouling becomes caked in the rifling after a few shots, ruining accuracy. Lubes formulated for Black Powder lubricate the bullet AND keep the fouling moist and soft, so each succeding shot can wipe away the fouling left behind by the previous shot.
A proper Black Powder load will have some provision for putting a BP specific lube like SPG onto the bullet. For pistol length barrels you can get away with a technique called pan lubing. If The Frontier Spot ever comes back on line there is a post on The Dark Side page about pan lubing. If you can't find it, send me your e-mail address and I will send you a copy of Pan Lubing 101. You can also buy bullets pre lubed with BP friendly lube on line. Lastly, you can cast your own. There is a new design, called the Mav-Dutchman bullet specifically for 44 cal BP shooting. It carries enough lube to keep your pistol running all day.
Regarding cleaning. Most of the corrosion associated with Black Powder was from the combination of BP fouling and corrosive primers. Now that we don't use corrosive primers anymore, BP is no longer so corrosive. I shoot BP in my rifle, shotgun, and pistols at every CAS match, and may not get around to cleaning my guns for a week or so. If you do it right, it is not a problem. The reason BP fouling corrodes guns is because it is so dry it wicks moisture out of the atmosphere and holds the moisture against the steel, causing corrosion. If you remove the fouling, OR get it oily, it cannot wick moisture out of the air and will not hurt your guns. You must clean them eventually, but you do not have to do it immidiately. I do this all the time.
I must admit, I shoot nothing but BP out of my Cowboy guns, so I clean them with a special mixture. Nothing will clean BP fouling any better than water, hot water is better. But the problem with water is getting it all out again. I clean my BP guns with a mixture of Murphy's Oil SOap, Rubbing Alcohol, and Hydrogen Per Oxide. In the BP world we call this stuff Murphy's Mix, and it has been around a long time. Just mix them together in equal proportions. The Per Oxide (drugstore variety)is really mostly water, and the alcohol is about 30% water. That's what does the cleaning. The alcohol helps the Mix evaporate quickly, the Per Oxide gives it a little foaming action, and the Oil Soap leaves behind an oily residue that coats any remaining fouling and renders it harmless. Smokeless shooters do not realize that cleaning BP fouling is actually easier than cleaning Smokeless fouling. Yes it is messier, but it requires far less elbow grease. There is never any leading, there is no copper jacket residue left in the bore, and there is far less elbow grease needed to clean BP than Smokeless. And Murphy's Mix is not toxic like Hoppe's or most other Smokeless solvents. It won't hurt you to breath it, but it will sting a little if you get it into an open cut, because of the alcohol.
With your Blackhawk, the easiest thing to do is remove the cylinder and dunk it right into a cup of Murphy's Mix. Then use a bore brush to scrub out the chambers. Use some Q-tips to clean out the cylinder base pin hole, and lightly scrub off the outside of the cylinder with a bronze bristle brush. Done! It's clean. Dry it off with dry patches and lightly oil it. Takes about 5 minutes.
Now grasp the pistol by the barrel and run a bore brush soaked in Murphy's Mix through the barrel a few times until the bore is clean. Inspect it with a dental mirror and a bright light. Another 5 minutes. Take a bristle brush and scrub the inside of the frame where the cylinder sits. Pay extra attention to the corner below the barrel, and the corner up just above the firing pin. FOuling tends to build up in those two places. Take a few Q-tips and liberally coat them with Murphy's Mix. Run them right into the window in the frame where the hand pokes through. Run several through there, slopping lots of Mix inside where it will coat any BP fouling that made it's way in with oil, rendering the fouling harmless. Take a few Q-Tips and clean any other nooks and crannies around the frame with more Mix. When done, dry out the bore, dry off the frame, and lightly oil everything.
This is the way I clean my Colts after every match. Takes about 15 minutes per pistol. Once a year I take them completely apart and clean out the black oily goo that has been left inside. Be warned, it will look ugly, but the oil has rendered the fouling harmless and there will be no rust.
Specialty of the house and it's still moving. That does it, this place gets no more of my business.