I'll offer an opinion.....and I'm not an expert....just a guy with a lot of shots behind him....ok?

There's two things you need to remove from your barrel....

1. powder residue

2. copper fowling.

This isn't a .22 rimfire where you're trying to remove lead!!!!

If you remove the copper fowling, you've also removed the powder residue.

Find a (ammonia smelling) copper remover...Sweets is my brand.....and using a bore mop, swab the bore a dozen times with the copper remover. Let it set.....have a couple beers.....swab it some more....have a few more beers.....and then using a phosphor bronze brush........brush the hell out of the bore...at lease ten complete strokes and then with a new dry mop, flush the bore clean.....one more time, using a lightly lubricated mop...swab the bore to leave a lightly lubricated effect.

As far as I know, there's no test for clean......but if you do this......you'll be in good shape....

Most barrels don't need this harsh of cleaning but every hundred rounds....but this style of cleaning is actually good for the barrel......not harmful at all.......I never recommend use of the stainless steel brushes....