Sweet's 7.62 is what i would highly recommend.
Rather...first a treatment with the foamy bore scrubber stuff, then hit it with Sweet's and a copper brush.
Did this once on an old Mosin. I had cleaned the Mosin using regular methods and materials, and gotten it mostly clean...i thought. Patches were still coming out a bit grungy, so I tried the Sweets.
Man oh man....there was gunk coming out of it for days (figuratively speaking). I kept scrubbing and swabbing and scrubbing and swabbing, and the gunk coming out went from black, to grey, to green.
I wonder if that rifle had ever been cleaned during the war (II)...or since. All kinds of copper fouling.
In any case, I'm sure it will help break up the junk in your rifling.