Casing being scratched

[Kswhitetails]

So, having the second round completed, and still getting small scratches close to the outer shoulder, I stripped things down and this time I worked the barrel out of the tunnel in order to more closely inspect the chamber itself visually. I discovered some things. First, take the barrel out of the upper to attempt any of this stuff. It's worth the extra work and time to gain more access to the extension teeth. Second, go ahead and polish your extension while you're here. It's too easy, and too worthwhile to allow things to go on as they are, polish the ramps folks, polish the extension teeth folks. So much better than a rough file job in the long run, and you'll feel really good about yourself at the range. I will be taking all my extensions out and hitting them this week, except for the LaRue. I'm not letting the pixie dust out of that upper yet.

So here's the long and short of my thinking at the moment. I believe the extension was rough, sharp edged, and that caused the bolt to be able to raise a burr during initial firing and chambering on the bench. There is no way I can prove this, but common sense says that this was the case. After finding the burrs all seemingly coinciding with the location of the bolt lugs when spun into lock position, I think I'm right here. The raised burr was making the deep gouges you see in my above pic. After I knocked the burrs off with the stone in my dremel, no more of the horrific gashes.

Since this step, I've also begun to realize that the chamber seems rough, and is the real cause of the scratches we are seeing. So while I had it down and exposed, (and knowing now that the foam ear plug with some polishing paste didn't take care of it completely), I realized it was going to take more aggression to clear it. I took a ProShot 45 cal copper brush, chucked it into my cordless, dipped it into my SeaFoam, and went low speed slowly in and out for around 3 mins, which made some nasty oil. After cleaning the chamber and bore, I went back and ran another two mins slowly in and out, and cleaned the chamber and bore again.

At this point, I put a cotton rag into the chamber to prevent unwanted contamination, and got out the dremel again. Back to work on the extension teeth, and the feed ramps. (reference above).

Untitled by ., on Flickr

You can still see the tool marks in the feed ramp, but they aren't anything like they were before. After a good cleaning of the entire thing inside and out, and another few swabs with a slip2000 patch, it came pretty clean.

Untitled by ., on Flickr

You can see the remaining copper off the brush at the forward section toward the shoulder inside the chamber, which still indicates a roughness exists, but rounds drop in and out so smooth it didn't seem like it would be much of an issue. I put it all back together, re-torqued, loktited, and let set up. I went to the range with 10 rounds of new BLACK ammo, and lo and behold, the magic happened. 4-430 ejection, 13 feet away. Standing. And the bcg travel seems quick, and MUCH smoother. Almost too quick. I probably need an H2 or similar buffer now. I can tell you, it's smooth like the Larue, or my 5.56 BCM. Not quite the same, but much bettah Grettah.

As for the brass, there is still some scratching, but it's so hard to get a good picture of it it's hardly concerning. The function and brass condition has been rendered better off than "usable", and I can't believe there would be any accuracy issues with what remains. My gun works like it should, and my brass is nigh on perfect. The only scratches that remain are hard to find, hard to capture a picture of.

Untitled by ., on Flickr

I do believe this is a manufacturing issue, although I have enjoyed what I've learned by taking the actions I have to attempt to fix it. There has been no skin off my nose, and I know my build is better for it. The finish of the bore is night and day from the chamber, it was mirror like when new, and still has that sheen. The nitrided surface of the barrel is indeed hard folks, my GB is a steel set screw type that was so tight I've had to wrench on it to get it on and off. I was thrilled it was tight, but thought surely it was going to mar up the barrel finish. No such worries. This things tank like. The gas block was leaving steel behind, and a quick wire brush cleaned that up. An oil rag, and it looks new. (keep in mind, I've now done this three times)

I'm now confident to the point that I will put my optic on, a target up, and see what it'll do.

And by the way, it's not just our group buy barrels. I peruse FB groups I'm in every day, and one about Grendel I'm in had an interesting post. Aparently, there are Faxon match fluted barrels doing the same thing.

I took a screen shot of the guys post from FaceBook; he bought a 20" Faxon Match fluted for himself posted this picture there:
Screenshot from FB by ., on Flickr

This is in no way a bash on Faxon, they make top shelf stuff as far as I'm concerned. They do seem to have an issue starting however, one that should seriously be addressed before it makes any larger a stain on their stellar reputation. I will also say that any manufacturer, when tasked with making a drastic increase in their part output, tends to have a few groans and pains as things get up to speed.

I would buy another of these barrels without hesitation. But I would do some things before I assembled and went to the range. First, I would polish the feed ramps and round off the corners of the extension. Second, I would polish the chamber with some 1000 grit plus compound and a 20 ga mop. I would then clean things up, assemble it into my upper and snug things only. No loktite yet. I would then go fire 30-50 rounds of ammunition, observing feeding/ejection/brass condition; and bring it home and take it apart. Clean it well, then inspect the brass, chamber, and extension to see what things looked like. If it isn't scratching the brass deeply, and is operating as you would expect, then re-assemble with your final build list.

Is it more work? Yep. Worth it? I think so. Should we have to? Nope. Send your upper to me, and I'll do it all for you. I'm looking for a job anyway. <Grass roots smiley face>