You need to clean smarter, times change, technology moves us forward.
Get a bottle of Boretech's Eliminator copper solvent, follow the directions. They even have a more heavy duty cleaner, CU+2.
Both will get rid of copper like now, get a stainless steel jag, that way you don't get a false positive from a brass one.
This stuff is non hazardous, very light smell but nothing that will drive your wife crazy! You can use it indoors or out, whatever you need to do. By far one of the best cleaners on the market.
Just don't order it from them, they have some weird shipping costs. Get it from one of the big box gun stores.
Spot on, I don't worry about the jag though. It saved my marriange as Hoppe was doing my wife in, only place I cvould clean guns was outside (kind of hard raining)
I will add that most guns suffer more from Carb on and the Carbon Killer 2000 (also non haz and non smell) works wonders and is my go to.
I had a bit of copper streak in my 06 target a month back and cleaned it out with the Bore Tech.
A help is the LYman bore scope. Its not precision like Hawkeye but you can see if you are getting clean. Ergo, that is how I spotted the copper streaking.
For the Carbon Killer I take my cleaning stuff to eh range and I clean when the barrel is warm. It makes it faster. I used an eye dropper to drizzle on a nylon brush, then thorough the bore, drizzle more on when its out of the bore on the front, then a few stroked, a dry patch and repeat until clean.