The tubing sounds like the best idea. As for shooting it out with some powder put in the drum hole does not sound good because the burning powder would just blow through the wire brush. As for cleaning, this method has worked for me for over 30 years. I allways take the muzzle loading rifle apart, I take the lock off, the barrel out the of the gun the niple out of the drum I never remove the drum. I make a solution of hot soapy water in a 3 or 5 gallon bucket drop the lock in it put the breach end of the barrel in the bucket, using a jag of the proper size wet a patch with the soapy water work it in and out of the barrel keeping the barrel down in the water this will cause suction and pull the water up the barrel I keep doing this until the patch starts to come clean. I put a new wet patch on the jag and repeat. This patch will come clean as a whistle in a minute or so. I then rinse with clean cold water from an out side hose. I then clean the lock with a tooth brush in the soapy water. I use an air hose to blow the water off of both them I spray with WD-40 blow them off with the air hose, wipe the bore with a clean dry patch or two, I have never had to clean the triger assembly accept to wipe it off with a clean rag and oil it lightly. I usually use a rubber tipped air chuck that will assure a tight seal at the muzzle end of the barrel and this will get 98 percent of the water out and the dry patches will get the rest. Be sure to use some rust preventive in the bore. I have never had a rusted bore or rifle. Also be sure to clean around the drum with the tooth brush. I have never had to use more than 4 patches to clean a muzzle loading rifle. This sounds quite envolved but it takes less time than it did to write this. I have heard some bad things about WD-40 and guns that are blued and browned barrels but don't believe it. I have been using WD- 40 on my guns for over 35 years and have never seen any degrading of the bluing or browning.