Bolt Damage.

[TomMcC]

Just so I understand, it's your view and or experience that that would be reasonable wear to the lugs with that particular setup?

[Dino11]

Looks like it is just getting worn in. Was it put on a new barrel?

You will have accelerated wear at first until things settle in.

I would shoot it, but keep an eye on it, doesn't look like wear on the rear locking surface. But that is what I would keep an eye on.

I would mic it and check it with a mic every now and then.

[Pappabear]

This particular Bolt/BCG has less than 1000 rounds on it currently, but is probably well over halfway there by my best guestimates.

I know what my opinion is, but I'm curious what the collective minds on M4C think. Does this look like excessive damage on the lugs of this bolt?







Barrel: Colt 11.5" with a BRT .063 gas block insert.

Surefire SOCOM RC2 suppressor

Upper receiver: BCM

Buffer Assembly: Geissele Super42 H2

Bolt: The brand and design is recognizable, but I'm going to refrain from naming them until I hear back from them.

I've not experienced any failures of the weapon thus far, but upon cleaning it after zeroing a new RDS mount, I noticed the wear.

What do you guys think? Soft metal from a bad heat treat process? Something else? Am I just seeing things?


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This got me curious so I got out 5 guns with those bolts and none looked like yours, NOT normal wear. Probably still run fine but id be concerned about them breaking further on a duty use gun.

PB

[Dino11]

That is not wear, this is an enhanced bolt and it was machined like that to aid the coupling and locking of the bolt.

Your standard bolt is not going to look like that one.

Just keep an eye on it, and check it from time to time for any more wear,cracks,missing lugs.

It looks a lot like the LMT enhanced bolt.

[Rogue556]

A Shorty with a can is going to wear quicker. I'm not sure what you're expecting to find -- a pristine bolt with no wear at all on the lugs? I'm not sure anyone makes a bolt like that.

I understand that. The Colt I mentioned with 10k+ rounds was chopped to 10.3" and the port was opened up to .070 around the 6k round mark. It's been shot suppressed with the same Surefire RC2 since that time. It's got some of the usual wear as you'd expect (anodizing missing, etc), but nothing like this bolt in question with significantly less rounds on it. Of course I do realize that just because one bolt with a high round count looks ok, doesn't necessarily mean one at a lower round count can't look worse.

From my understanding, the bolt in question is made of Aermet 100, which is thought to be two to two and a half times stronger than C158 when both are properly treated. Of course I could be wrong on that. The gun with the issue is ported more conservatively than the Colt with the original C158 bolt, so it just seems odd that there would be such a large difference on a bolt that's durability is often touted as being superior.

This got me curious so I got out 5 guns with those bolts and none looked like yours, NOT normal wear. Probably still run fine but id be concerned about them breaking further on a duty use gun.

PB

Thank you for the info Pappabear, I was hoping someone with more experience with these bolts would chime in. This gun was in the proccess of being vetted for home defense use (I consider all of my guns in that category though, so that's not saying much). It was going to be a night vision/bedside gun, but that'll wait until I verify something else isn't wrong. Luckily I have a few spare BCM bolts to get it running again.

I emailed the company just before creating the thread but haven't heard back yet. I'm going to see what they say.

Some more pictures that show the damaged areas a bit better. There are definitely spots where metal has been deformed, causing burs.






















Here is a picture of the barrel extension and chamber for reference.







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[Dino11]

Now those pictures are much better, I retract my statement about using that bolt.
The metal is smearing from being to soft, get it replaced. Sucks to get old, your eyes are the first thing to go.

Keep us updated as to what the vendor does for you, and who the vendor is. I was going to get an enhanced bolt for one of my guns that is coming up due pretty soon.

[Pappabear]

I'm just the opposite, the initial pictures looked like much larger chunks missing from the bolt. So I'm not sure. I will be interested in seeing what The Great LMT has to say. There is no bigger fan than myself of this company. Whatever they conclude, I would take as solid.

Interesting case.

PB

[sig1473]

Reminds me of mine....
[IMG][/IMG]

~2K Rounds

[Leonardo]

That is not wear, this is an enhanced bolt and it was machined like that to aid the coupling and locking of the bolt.

Your standard bolt is not going to look like that one.

Just keep an eye on it, and check it from time to time for any more wear,cracks,missing lugs.

It looks a lot like the LMT enhanced bolt.

Take a good look at the provided pics. I think you will see that it is NOT made that way, nor is it normal wear

[alx01]

Barrel extension looks fine so misaligned barrel/upper is not the problem. Bolt definitely has some obvious pinning on a few locking lugs. Not sure why it affects both front and back of the lugs, but with 1k rounds I would be concerned.

If you look at the tech section this particular manufacturer BCGs/bolts have had a number of issues recently (last 1-2 years). I understand why people want to buy "enhanced" parts, but I learned that most of them are either nothing more than marketing or theoretical engineering improvement without any real-life extensive validation. With USGI/mil-spec parts at least you know what you're getting in terms of durability or longevity.

I posted it before and will post it again: