Like someone said, this topic is good for lots of different opinions........ here is my two cents worth. Some will certainly disagree, but it works for me. Also keep in mind, I keep my barrels clean, I do get a little more aggressive when a buddy brings me a rifle that is 20 years old and never been cleaned......
First of all, I almost never use a wire brush and NEVER in a custom lapped barrel.
Second, always start the patch (or brush) at the breech end and use a boreguide. Go one direction only and NEVER reverse either patch or brush while in the barrel, and never pull a patch back through the barrel in reverse after it has been pushed through from the breech.
Step 1, Insert boreguide
Step 2, Run patches with automotive brake cleaner through until they start to come out clean. Usually takes 3 to 4. (removes powder fouling and carbon)
Step 3, Run patches with 50 BMG copper solvent through until they come out with no blue.
Step 3, (alternate) Fill bore with foaming bore cleaner, allow to sit for 30 min, repeat, then push through 2 clean patches. Push 1 patch with 50 BMG check for blue, if blue, repeat.
Step 4, Push through 2 patches heavily wetted with Kroil.
Step 5, Push through 1 dry patch
Step 6, Remove boreguide, swab chamber with a clean 12 ga shotgun swab.
Step 7, Lube bolt lugs
Done......
I typically clean after a maximum of 20 rounds.
Some factory barrels may require more aggressive cleaning, but most will not if copper or carbon is not allowed to build up in the first place. A factory barrel with a fairly rough finish may need to be cleaned after as little as 10 rounds to avoid too much copper build up. As a general rule a good custom barrel will not build up copper quickly and will not require as aggressive a cleaning process.