Been shooting various maker's barrels since 1972. I've never had to "polish" a barrel yet including cut barrels by Bauska (.450" with .028" deep rifling - .506" groove to groove),
Rice, some unknown .32bl. with narrow lands, a weird deep buttoned barrel by Hall Sharon in 1975, buttoned TC barrel in 1972, Green Mountain, Getz, GRRW, & Bill Large - that about sums them up.
Learned in early 1970's to use a .005" undersized ball with .022" denim patches, wet with lube and have at it. Good accuracy right off the bat, without fail, except for the GRRW barrel.
It now shoots well with the thin .021" to .0225" denim patches. When new, I had to use a 12 ounce denim I measured crushed in calipers at .030" and .025 in my mic. due to the reamer
marks being too hard on the patches. Now that it has been shot over 5,000 times, although the reamer marks are visible, they are only a memory. The bore is smooth.
Even the .004" deep rifling of my TC Hawken(s) liked the .495" ball and .022" denim patch, but with 85gr. 2F GO then GOEX or Curtis and Harvey.
One guy at the range was having trouble loading my recommended load in his .50 TC(H) so I recut his crown with a sharp pocket knife, then polished it with a piece fo 320 emery from my pocket.
Total time, might have been 5 minutes. It loaded nicely after that.