With muzzleloader barrels, much like the “un-mentionable” rifles, , the difference in tooling marks between many of the factory grade and custom barrels are generally quite pronounced, and the effects on accumulated fouling, cleaning, and sustained accuracy, comparable. The OP’s photo is quite representative of several of my barrels(modern and muzzleloaders) that I have bore-scoped. From a hunting/casual target accuracy standpoint there seems to be little effect given attention is paid to swabbing the accumulated fouling that is trapped by the rougher bore finish. The finer finish of the custom barrels, in my experience enable the shooter to maintain accuracy for a significantly higher number of shots between swabbing, as well as much less time/effort when cleaning. IMO.
