A few weeks ago, I had posted about a failure to extract issue with an AK74 using a U.S. made barrel. (Link here). The chamber was covered with what appeared to be a uniform brown coating, which was obviously what was causing the cartridge to stick. I thought the issue was solved when I made my earlier post, but the fact is that I could not clean the gunk (or whatever it was) out of the chamber with Hoppes, a copper solvent, or even carburetor cleaner.
I subsequently purchased two more cleaning products: "Goof Off," which is formulated to remove latex paint, asphalt and tar; and Rust-Oleum Rust Stripper (which I specifically selected because it was acid based). Alternating between these two products, which I applied to Q-tips for the actual cleaning, I was able to clean out the coating.
If it was rust, I am thoroughly embarrassed. However, I'm not sure it was. I have used corrosive ammo before in other weapons, and I've never seen anything like this before. There was no sign of corrosion in the barrel or on the gas piston--it was all in the chamber, uniformly distributed, and stopped in a clean circle about 1/8 inch from the bore. It came out somewhat irregularly, with jagged edges to some areas, and it truly appeared that something had coated or been applied on the interior of the bore.
Due to weather issues, it will probably be a while before I can test the rifle out again. Rest assured, I will report further extraction issues, if I have any. Given the lack of information I was able to find on the internet on solving this issue (even though I came across enough items to suggest that this is not an entirely rare issue), I hope that this is of some help to someone.
(Update: I was able to test fire the rifle again a couple weeks later and it functioned reliably--I shot 90 rounds through the rifle without any problems. After returning from the range, I immediately cleaned the bore with both the ordinary cleaners and the "Goof Off").
The most important thing to use on your AK74 for cleaning is sudsy ammonia. Ammonia will instantly counter-act the salts from the corrosive Berdan primers.
ReplyDeleteI use "Fantastic" which I pick up in bulk at Costco, but the cheaper stuff that you get at Walmart is just as good.
Spray the ammonia cleaner down the barrel, the gas tube, and the muzzle device. Scrub what you can with a plastic bristled, tooth brush, and use the rifle bore brush to scrub the barrel. Then rinse with lots of hot water.
Pay special attention to the bolt, bolt carrier and chamber. The ammonia cleaner will also take off any built up lacquer from the casings.
In a grid down situation, where ammonia is not to be found, you could use urine to counter-act the corrosive primer salts.
Thanks for the info. I hope you don't mind, but I am going to copy your comments to its own post.
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