I'll start by saying cleaning my rifles is one of my least favorite things to do, and I find joy in letting them run and run when filthy. That said, I decided it's time to clean DD MK18 10.3" upper. This is a chrome lined barrel that I run suppressed with a surefire 212 100% of the time. I'm unsure the last time I cleaned the rifle but I might estimate in the 1000-1500+ round area.

Working on this upper, I've got some kind of fouling in the first 1.5-2" of the rifling that looks almost like sandpaper. It appears to be rough in texture and dark colored. I've been working on things almost 2 weeks now in the evenings. I've used a combination of foaming bore cleaner that continues to come out blue/ black, sweets 762 with a nylon brush and hoppes 9 that soaks over night or scrubbed with a brass brush.

It seems no matter what I do, I can't get the fouling out of the first couple inches of rifling. I assume it's carbon but geez it's like I'm making zero progress. Any thoughts on how I can get that out of the chamber?

I'd love to put up a pic, but I can't get the lighting to work out where my phone can capture an image. Any ideas are appreciated.

Ultrasonic cleaner?

Have you tried a brass brush?

Suppressors Sunday a ton of burnt powder back down the bore when a case is extracted.

Yes, I've been using a brash brush with hoppes 9 occasionally. It seems like I've seen some improvement, but the amount of improvement has dramatically slowed.