Don. If the crud is partially dried lube, then new lube will act as a solvent and do as you suggest. However, sometimes, the lube on the patch doesn't last long enough to protect the whole barrel. If you shoot a mountain rifle, or some other gun with a barrel that is 35 inches or shorter, you may never have the problem. I didn't have the problem in my 25 inch caplock gun either. But, when I had my 39 inch barreled .50 cal. rifle made, I had problems with dried residue caking on the last few inches of the barrel. At first I thought maybe I had left some oil, or soap in the barrel the last time I cleaned it. But after scrubbing, and then using alcohol to clean out any oils, or soap, I still had the problem. On examining my patches, they were much drier than I was used to seeing and feeling with my older rifle with the shorter barrel. I read, and thought about it for months, going through back issues of Muzzle Blasts, talking to older shooters at the club, and found a couple of guys who were having the same problem but just were using a bore brush on the gun barrels after every 5 shots or so. When we looked at their patches, we found the same thing. Too dry. They had lubed the patches either at the range, or at home within 24 hours of coming out to the range. We checked all our patches in our range boxes and they were holding as much " wonder lube " as the cloth would allow.
Ergo, something was happening in the barrel. I could not find a way to add more lube behind the ball that was consistent, so, after watching some chunk gun shooters lube their barrels after loading the PRB, it dawned on me that they had the solution. They also tend to shoot very long barreled guns- 4 feet barrels are not uncommon. I tried, it, shot some rounds over a chronograph, discovered a small increase in velocity, but a much more noticable drop in SDV, and NO MORE crud in that last 6-8 inches of barrel. My brother talked to some of the chunk Gun shooters, and they also reported no problem with caking residue at the end of their barrels.
I think we found the solution to the problem. BTW, in BP cartridge guns, where long barrels are also the norm, they place a pea of soft lube between an Over Powder wad, and a thin paper wad that protects the base of the bullet, to add lube to the barrel over and above what is in the grease grooves of the bullets. I laso understand that some of those shooters also lube the barrel before each shot, but I have not witnessed that, or spoken to someone who does it personally.
