Yeah, may be the batch of ammo I recently bought. Same kind I have always shot through it, but it seems the chamber is really gummed up more than usual and there is only so much a cotton swab and solvent is getting out.
Chamber grunge is usually due to incomplete case obturation... that is, the case is not sealing completely against the chamber walls, allowing gas & grunge to flow back alongside the cartridge case. Ever notice black smudges on your brass? Bingo. This is particularly seen with lighter reloads, such as some of us who have become recoil-sensitive use to make practice sessions a bit more tolerable.
As mentioned, I simply use a brass/bronze bore brush of larger caliber; .40 in 9mm, .45 in .40, and I order .50 caliber brushes from Brownells' for my .45s (cannot find these locally). Used on a short, non-rotating cleaning rod, these do a good job of scrubbing the chamber when inserted to the proper depth and rotated by hand. The extruded aluminum rods (the ones with the loop "handle") that used to come with S&W revolvers are perfect for this task.
I've never had chamber fouling the way I do until I started shooting the Winchester 124gr NATO. The gunk just gets plastered to the inside of the chamber. Almost need to scrape it out. I'm not changing ammo though. I love the way the casings shoot out of the chamber while using this ammo. I just soak the barrel a bit longer and use a Q Tip directly in that area to get everything out.
Chamber fouling is usually pretty easy to get loose. I usually use a broken off Q-Tip and just scrape it off. This gets the big chunks out of there. I also use JB's Bore cleaner to get the carbon out of the barrel every few cleanings.
The chamber area is one area where I do try and get really clean after every cleaning.
This is the best thing I have found for cleaning a chamber. . . heck, it's great all over the entire gun. Won't remove even the most delicate bluing yet easily cleans all gun grunge and even lead. Similar to copper Chore Boy but way better, and made specifically for guns. $5 delivered to your door. . . I am still on the same piece from about 5 or 6 years ago. Best $5 I ever spent.
Oh, and one more thing: I like to use a bamboo skewer for scrubbing detailed spots (like the chamber step). It really works well on carbon & grunge, yet it won't scratch or harm anything (plus they are REALLY cheap).
A forum dedicated to and laser-focused on Heckler & Koch firearms, Heckler & Koch accessories and the owners and enthusiasts that love them! Come join the discussion regarding HK pistols, long arms, NFA arms, HK accessories, HK history and trivia and more.