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Posted: 5/25/2004 12:25:23 PM EDT
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This one's been bothering me for a while. One of my uppers has had a consistent problem with bolt stickage during storage. I rotate three uppers around a single (preban) lower, and the bolt sticks sometimes n one of the Colt uppers. It sticks so tightly that I have to turn the upper upside down and hit the charging handle with a rubber mallet to get the durn thing out. This only happens when I haven't used it for a little while, never during the course of fire. Each time this happens I inspect the entire bolt assy and the interior of the upper and, to date, haven't found anything to indicate where the sticking is happening. There aren't any telltale wear areas on the bolt assy that match up with the upper - other than the typical wear you'd expect in a fired AR. At first I though it was the rear of the bot carrier sticking to the upper in the area just above the rear takedown lug, but I haven't been able to conclusively determine whether that's the cause. Anyway, on to my question. This time, in disassembling and inspecting the bolt assy itself, I noticed a coating of a green (!) something on the bolt just outside of the gas rings (where the carbon builds up on the back of the bolt, at the opposite end to the extractor/ejector). It was a pretty tough substance, but I was able to scrape off most of it using my fingernail. Then I looked inside the bolt carrier and noticed the same substance on the inside of the bolt, down on the circular face where the bolt slides in (this is hard to describe). I disassemble and clean the bolt assembly after every shooting session. I don't scrape off the carbon and lube using very little Militec-1, generally a bit on the extractor, a bit on the ejector, and a bit on the rest of all the bolt surfaces. What is this green stuff? |
I'm shooting SA battlepacks.
So that means the residue is corroding...and hopefully not my bolt? |
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There have been rumors that some lots of SA are corrosive, but no definitive proof of such claims. Should also note that miltec-1 is not a very good corrosion inhibitor (I am of the personal opinion it promotes rust, but that is just a hunch of mine, no proof to back it up). I would try Breakfree and see if that helps. I generally use breakfree for lube and protectant and have had no issues with corrosion when shooting SA and leaving the rifle uncleaned for long periods of time. Once though, I used a different lube and left a rifle unclean for two weeks after shooting SA. During cleaning I noticed some encrusted buildup on the cam pin and when it was cleaned off, some minor pitting on the pin was noticeable. No signs of corrosion anywhere else on the rifle. This was a fairly new rifle so I know the pitting wasn't there beforehand. Weirdest thing, still don't really know what caused it but haven't had the guts to shoot SA with the same lube since. |
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