My pop shot an old 03A3 for years killing deer and just about everything else he pulled down on with it. He mostly only shot surplus ball ammo after replacing the bullet with a 150g Sierra spitzer. Average groups were around 2-3" at 100 yds. After he passed on, I got the thing out and decided to see if it would clean up as the tube looked horrific. I spent nearly a day scrubbing and letting it soak then scrubbing some more. After which, I could still see crud in the barrel. I decide that, I really had nothing to loose but the barrel, and ran some J-B paste through on as tight a patch as I could shove through. After doing this several times I followed up with some Sweets, and got some major crud out.
Well since prior to this I was getting clean patches I repeated the process a couple of more times. Each time I got more crud. After about three or four of these rounds, I went back to the standard cleaning solution and then reinspected the thing and it was almost spotless. I let it soak over night with a 2-1 mix of Shooters Choice and some Kroil. The next morning it only took a couple of passes with a brush and a few patches and it was squeeky clean. Now the thing will hold groups around 1/2" at 100. Now this might not be the case with your friends rifle, but if you haven't tried something similar, you might be surprised.
I am sure that the barrel has some undesirable marks through it, but from the way it was, to the way it is now, is like day and night.
