Very Helpful Commenter, who once sent some very nice information on how he moved the front sight and cut down the barrel on a SKS, had mentioned that he had had such good results in his black-powder guns with 1000 Wonder Lube, he'd started using it after this ammo. The other day he sent this:
I took my M-N 91/30 to the range the day after I emailed you and shot forty rounds of "Com-Bloc" corrosively primed ammo through it. I also shot forty rounds of 1943 SA MkVII through my unissued #4 Long Branch Enfield. I wiped the bores with wet patches when I got home, then wiped the bores with a flannel patch coated with 1000 Wonder Lube. This morning I examined the bores on both of 'em to find no rust, just shiny rifling. Same with my .50 TC Hawken that I put 125 shots through last Sat. Every shot was with a 1000 WL patched round ball and 50 grains of 3f Goex, my target load of choice. Again, no rust, just shiny rifling. BTW, no wiping between shots, the last one loaded as easily as the first.
I'm going to have to get some of this stuff to try.