A stainless barrel holds up better than a normal barrel.
Sweets is very strong and is only used when you have to. Like others said, it should be cleaned out afterward.
Hoppes #9 has no ammonia & is safe.
Butch's is sorta like Hoppes with some Sweets added. That is what benchrest guys use, (& myself).
One piece coated rod used from the chamber end makes a huge difference.
Many mentioned a factory barrel being so rough that it "grabs" a lot of copper. You can quickly polish the barrel yourself to fix this. I'm not sure of the exact instructions, but what you do is fire 10 rds & see what it takes to clean it. Follow this with 10 rds where the bullet is LIGHTLY coated with J-B BoreShine paste. Now clean again & see if there is a lot less copper. Maybe repeat once. I'm not an expert on how to do this, but many swear by it.
It's called "Fire Lapping". J-B is a very mild abrasive.
Supposedly improves the groups of all factory barrels.