"new unfired, never mounted" barrel...but it ain't

[Hdog83]

Bought this LMT MRP 300BLK 10.5" barrel on TOS EE. The condition description in the listing said "new unfired, never mounted", and the price was right, so I pulled the trigger over the weekend, even though comms were initially a little spotty. I finally picked up the box this morning from my PO Box.

Up front admission: shame on me for buying there. I promise I won't do it again.

Anyway, what I found inside the box has me puzzled. There are mounting/use marks & scratches all over the outside of the barrel extension, flash hider and gas block, so I know the "never mounted" part is a bald faced lie. There is debris (powder fouling?) in the barrel, and some corrosion on the gas block in front of the end of the gas tube. The rifling looks good, but I don't have a bore scope. Mysteriously, the feed ramps themselves look untouched. What I'm most concerned about is the area around the lugs. Is that corrosion or pitting? It doesn't look similar to other MRP barrels I have.

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To those who know what they're looking at better than me, should I be concerned (and try to reverse the transaction), or should I just chalk it up to experience and use the barrel as is? Many thanks.

[glock21xxx]

Bought this LMT MRP 300BLK 10.5" barrel on TOS EE. The condition description in the listing said "new unfired, never mounted", and the price was right, so I pulled the trigger over the weekend, even though comms were initially a little spotty. I finally picked up the box this morning from my PO Box.

Up front admission: shame on me for buying there. I promise I won't do it again.

Anyway, what I found inside the box has me puzzled. There are mounting/use marks & scratches all over the outside of the barrel extension, flash hider and gas block, so I know the "never mounted" part is a bald faced lie. There is debris (powder fouling?) in the barrel, and some corrosion on the gas block in front of the end of the gas tube. The rifling looks good, but I don't have a bore scope. Mysteriously, the feed ramps themselves look untouched. What I'm most concerned about is the area around the lugs. Is that corrosion or pitting? It doesn't look similar to other MRP barrels I have.

4810848109481104811148113

To those who know what they're looking at better than me, should I be concerned (and try to reverse the transaction), or should I just chalk it up to experience and use the barrel as is? Many thanks.

I am no barrel wear expert so I’ll keep my analysis to myself...

Have you reached out to the seller? If so, what did that individual say?

[Jaysop]

Don't feel bad about someone else scamming you. I bought an upper on this site that was advertised as "like new" the dam thing was so filthy that I ended up hosing it off before even getting into a cleaning and tear down.

[Jwknutson17]

I would get a refund. Looks used to say the least. Mounting it just once will have slight marking on the extension, but not as bad as you have it. But anything showing on the gas tube would be from a lot of rounds. You can shoot 100 rounds and still have the gas tube looking new with a quick wipe down. Looks to be stored/put away wet. Those barrels come with a blue "rope" looking thing through the barrel, and cardboard sleeve over the end of the gas tube.

How did you pay him? I would be requesting a refund. You can also contact the mods over there, and they will step in also if needed. Lots of scammers on TOS.

[Hdog83]

Have you reached out to the seller? If so, what did that individual say?

I have not, yet, but I'm about to. As I'm not a barrel wear expert either, I wanted to ask the SMEs and near-SMEs on M4C for their views, so that I would not be making unfounded accusations to the seller regarding the condition of the barrel assembly.

If its only the "never mounted" part that's not true, I suppose I can live with that and move on. But the honest dealing part of me still doesn't like doing business with people who don't behave the same way....

If the "never fired" part is also untrue, then I'm significantly more inclined to ask to undo the transaction.

If there is something fundamentally wrong with the lug area / barrel extension, metallurgy or otherwise, that might affect safety, performance or durability, then I'm much more inclined to make a fuss / warn others off / etc.

That's what I was trying to figure out with my post and photos.

[Jwknutson17]

If you have any discoloration on the gas tube on the receiver end where it goes into the gas key, it, no doubt, will have had many rounds through it. New barrels that are test fired, from many manufactures will ship out with carbon, or whatever, in the bore. Take a new off the shelf rifle and run a patch through it and it will look nasty. But the gas tube will look brand new still.

A way to also know if the barrel was installed/fired as you will see the slight imprint of the carrier on the extension face. When the bolt slams home, the carrier will be resting on the extension and you would be able to see that. I cant tell from your photo.

[Hdog83]

Thanks very much Jwknutson17.


If you have any discoloration on the gas tube on the receiver end where it goes into the gas key, it, no doubt, will have had many rounds through it. .... But the gas tube will look brand new still.

Upon further close inspection, the gas tube looks pristine / brand new.


A way to also know if the barrel was installed/fired as you will see the slight imprint of the carrier on the extension face. When the bolt slams home, the carrier will be resting on the extension and you would be able to see that. I cant tell from your photo.

Another good idea. I looked carefully, but I don't see any imprints or wear from carrier impacts on the end of the extension.

I have multiple other MRPs, and it's obvious to me that this barrel assembly was installed in a chassis at least once. It also seems to have been banged around, given the scratches, but maybe it wasn't ever fired (other than LMT factory test firing). So, maybe much ado about nothing.

Still, I'm curious about the condition of the metal in and around the lugs. It doesn't look like the other MRP barrel extensions I have.

[Slippers]

LMT test fires every barrel, so there will definitely be marks on the extension where the chassis clamps. All of my spare MRP and MWS barrels have arrived with dirty bores, chambers, and locking lugs, along with marks and the occasional scratch through the parkerizing at various points including near the muzzle. The gas block on the original barrel that came with my MWS looks like whoever drove in the pin missed a half dozen times.

LMT is a lot like Colt as far as fit/finish is concerned. I'd at least shoot the barrel and see how it runs.

[Hdog83]

Very helpful - thanks Will.

I just checked one of my other MRP barrels - a new ("never fired") 5.56 14.5" that I have for sale on the EE here. This barrel came installed in a new CQB upper that I bought from Rainier when they were clearing out of their LMT stock last year. It has almost no visible evidence that it was ever installed in a chassis, the bore is clean, but the area behind (er, forward of-) the lugs is dirty, and there are scuffs on each of the feed ramps, presumably from test firing by LMT. The lugs on my "known-new" 14.5" don't have the discoloration / pitting / whatever that the subject 10.5" 300BLK barrel from TOS shows.

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So, less use markings than the subject 10.5", but again different visible cues from the lugs themselves.

(As an aside, I'm not looking for / expecting "clean room" clean. It's a tool, not a concours contestant. I just want to make sure it's OK from the perspectives of safety, durability and performance.)

[sinister]

I don't see a bolt carrier imprint on the barrel extension face nor anything that looks like impact or bolt turning wear. No center of feed-ramp coppering or gouging indicating magazine feeding. I see what looks like spot surface rust or staining, maybe from being stored someplace hot and humid. Your third photo if focused in macro might give a better clue.

The rust at the gas block where it's in-the-white would also be from somewhere hot and humid.

I don't think you can determine whether or not it's been shot (besides test-fired) without bore-scoping. The barrel extension tells me it's close to new (if not off-the-assembler's-shelf).

[Hdog83]

Thanks very much sinister - very helpful as well. It was apparently stored on a shelf, in a basement, in the southeast, so the rust / staining is more than likely a consequence of a hot and humid environment.

The overall update is that I ended up having a lengthy back-and-forth with the seller, and I'm satisfied that the barrel assembly is as represented, despite the cosmetic scuffs etc. The seller seems to know his LMT MRP and MWS stuff pretty thoroughly, and was able to compare my photos to other barrel assemblies he has on hand. We were both a bit puzzled by the lug discoloration, but I'm willing to chalk it up to LMT's manufacturing and processing. Now to mount it up, test fire/zero with factory ammo and then commence load development....

Thanks again to everyone who took the time to read this and respond, both publicly and privately - I really appreciate it.

[sinister]

Hope she hammers targets to your liking. Sounds like it'll make a nice rig.

[mark5pt56]

I agree, appears to be storage issues. A wipe down with a good oil would've prevented this.