I use only subsonic lead ammo and NEVER use a brush on mine. Just a few dry patches every 1500 to 2000 rounds. Or when accuracy starts to die off a little. Don't use a snake either because they have bore brushes imbedded in them. The lands and groves are so small that they will pull small amounts of brass from the brush and leave them in the barrel. Because of the lower bullet speed the rear of the bullet isn't deformed and the corners of the lands cut into the bullet just enough for consistent accuracy. (Match ammo helps too). Brass is abrasive to steel it just takes a long time but keep in mind that brushes are over sized as well. Once the sharp corners on the lands are gone so is accuracy forever. If you are using plated bulk ammo this does not apply and I would foam or solvent because that coating comes off in the barrel too. If my accuracy didn't improve from following this I wouldn't be telling you all this.
and yes it is the hardest thing in the world not to clean my favorite gun after I shot it all day.