In any of my bolt guns I just spray foaming bore cleaner or rem oil into the barrel and let it sit for a few minutes then run a bore snake through it.

But in my DPMS and S&W MP15/22, I'll take the upper off, bolt and slide out and clean everything I can get a patch, brush, or peice of cloth with my preferred cleaning agent to.

In the mp15/22 since the bolt itself is so much different from actual AR style rifles, all I do is wipe off any residue and spray some lubricant into the bolt from every possible angle. Hasnt givent me any problems cleaning it this way.