Because I was sent a few different handguards by Rainier Arms recently, I needed to disassemble and reassemble a few upper receiver assemblies. One of those was the 5.45×39 upper sent to me by Spike’s Tactical last year. It’s seen crate after crate of corrosive surplus ammunition, and has never been properly cleaned.
Coincidentally, I had just received a CAT M4 bolt scraper tool from Rainier, and thought I’d see how much carbon it would remove – there will be a separate post on that.
But the topic of this post is corrosion. Do you think that, after all the carbon was scrubbed and scraped away, I found corrosion on the nickel boron parts? What about the barrel, front sight base, and gas tube, all of which were Melonited? Here’s a current photo of the barrel and bolt carrier group. I’ll post more photos on October 5th.
Let me know what you think in the comments below.