For what it's worth.....friends and shooting buddies, Darrell Holland (Holland's Gunsmithing) and Chris Ditcher (Pac-Nor Barrels) did an experiment on a heavily carboned and copper fouled barrel (22-250). This barrel was cleaned first with just patches and checked with a bore scope. It was then cleaned 'normally' with patches and bronze brush w/solvents, checking progress with a Hawkeye bore scope along the way.
The real eye opener was when the barrel was sectioned on the milling machine to really check it out first hand. The ony way that barrel got really clean of all copper and carbon, was a through scrubbing with patches to wet the gunk, then repeated use of bronze bore brushes with solvent, then Witches Brew (Holland's). Nothing else got the barrel truly clean.
Now I use Kroil and Shooters Choice at 40/60% (a la the BR boys), and bronze brushes to scrub that barrel, custom stainless or factory, doesn't matter. If copper is present, the Barnes CR-10 gets used. When I get home from an extended shooting outing, I then use Witches Brew on a bronze brush, and baby oh baby, does that barrel ever get clean then!
You can kid yourself using only patches or nylon brushes, but if you think that harder than steel carbon is coming out with a gentle nylon brush workout, then you're only kidding yourself, believe me. It takes elbow grease, bronze brushes, and good cleaning compounds to get that crap out of a good shooting barrel. Below is my box of cleaning stuff....a bit more than patches and solvent.....
When you're all done using the 'other' methods, look at the muzzle at 45* to the sun outside. Chances are you'll still see traces of copper fouling on the lands and grooves. And guess what's lurking just ahead of your chamber that you can't see..... Oh and by the way, I go through about 4 or 5 bronze brushes on a good shoot....500 rounds or more. When you don't feel good resistance in the bore, time for a new bronze brush. Save the nylon brushes for copper solvent so it doesn't eat your brush.
