Fouling is layers of metal fouling and podwer fouling. Wipeot should work after a shooting session if the barrel was clean before shootong.
When cleaning a newly purchased used rifle, I scrub it with alternate applciations of Rem Clean (a mild abrasive) and a metal cleaner like Sweets 7.62 or Wipeout or Hoppes Copper Cutter. In a bad rifle, it takes alternate applciations, each day, for a few days to get it all out.
While the gunk is in the barrel, i store the rifle muzzle down, so crap does not flow back in to the action, trigger and bedding.