View Full Version : Probably nothin', but I'd like an opinion...
Had some modest range time with my rifle this morning, but shot enough rounds to get it good and warmed up. As I was wiping down/re-oiling, I noticed two things:
There is some type of divot on the mouth of the chamber:
http://img.photobucket.com/albums/v214/kry226/LMT003.jpg
Then found some rusty goo (gas leak) emerging from under the FSB:
http://img.photobucket.com/albums/v214/kry226/LMT002.jpg
This gun runs like a sewing machine and I have never had any malfunctions, but it does have a low round count thus far. I am certain there is nothing technically wrong with the rifle, but I wouldn't mind hearing any opinions. Not trying to keep the rifle brand a secret as I don't want this to be about the make, but it is a top tier gun.
Thoughts? TIA.
Had some modest range time with my rifle this morning, but shot enough rounds to get it good and warmed up. As I was wiping down/re-oiling, I noticed two things:
There is some type of divot on the mouth of the chamber:
http://img.photobucket.com/albums/v214/kry226/LMT003.jpg
Then found some rusty goo emerging from under the FSB:
http://img.photobucket.com/albums/v214/kry226/LMT002.jpg
This gun runs like a sewing machine and I have never had any malfunctions, but it does have a low round count thus far. I am certain there is nothing technically wrong with the rifle, but I wouldn't mind hearing any opinions. Not trying to keep the rifle brand a secret as I don't want this to be about the make, but it is a top tier gun.
Thoughts? TIA.
That little divot thingy is actually LMT's trademark or logo and was placed there on purpose...GTG on the first thing unless you have a beef with logos:D
Second part.....that rusty goo most likely is not a huge problem and should just serve as a reminder that your cleaning and lubricating is lacking a bit. The leakage of gas from the gas block will force a bit of rust or crude to creep out if it is present under the fsp or gb, esp. if you do not make a habit of really working that clp into the region surrounding the GB....but basically you just had a little rust under there that obviously is unreachable or cleanable without removing the fsp or gas block and since you stated you got it nice a warmed up and shot a nice bit of ammo through it, you just leaked off enough gas from the GB that it forced a lil bit of rust out....from now on just try to make a better habit of really penetrating that region with clp or similar substance.
That little divot thingy is actually LMT's trademark or logo and was placed there on purpose...GTG on the first thing unless you have a beef with logos:D
Wow. No beef with logos, just never read or heard of them doing that. I guess that explains the sewing machine part. :D
Second part.....that rusty goo most likely is not a huge problem and should just serve as a reminder that your cleaning and lubricating is lacking a bit. The leakage of gas from the gas block will force a bit of rust or crude to creep out if it is present under the fsp or gb, esp. if you do not make a habit of really working that clp into the region surrounding the GB....but basically you just had a little rust under there that obviously is unreachable or cleanable without removing the fsp or gas block and since you stated you got it nice a warmed up and shot a nice bit of ammo through it, you just leaked off enough gas from the GB that it forced a lil bit of rust out....from now on just try to make a better habit of really penetrating that region with clp or similar substance.
Would a little Kroil or PB Blaster work? They seem to be a couple of the best penetrants around and would certainly get under the FSB and displace moisture/prevent rust. Couldn't imagine it being detrimental to the gas ports.
Does the Rust seeping from the gas block indicate that the barrel isn't parkerized in this region?
Does the Rust seeping from the gas block indicate that the barrel isn't parkerized in this region?
It's most commonly found on guns like LMT and Bushmaster who indeed don't park under the FSB, but I'm not sure if there's a correlation.
Cagemonkey
05-11-10, 20:44
Does the Rust seeping from the gas block indicate that the barrel isn't parkerized in this region?I would think so, since The Chart mentions LMT's aren't parkerized under the FSB.
It's most commonly found on guns like LMT and Bushmaster who indeed don't park under the FSB, but I'm not sure if there's a correlation.
disregard....
Blankwaffe
05-11-10, 21:07
Wow. No beef with logos, just never read or heard of them doing that. I guess that explains the sewing machine part. :D
Would a little Kroil or PB Blaster work? They seem to be a couple of the best penetrants around and would certainly get under the FSB and displace moisture/prevent rust. Couldn't imagine it being detrimental to the gas ports.
Ive seen the corrosion around the base of the FSB even on barrels that were parked.Especially after being in heavy rain events etc..
I made the habit to just spray those areas down with a good oil/CLP.I dont think it matters what brand just anything that will creep between the surfaces and protect.
Otherwise I would not worry about it.
Belmont31R
05-11-10, 21:35
Parkerized parts rust, too, and even SS will rust if not cared for.
Probably just need to drip some oil all around the FSB, and let it soak in. I've had LMT uppers in snow, rain, mud, etc and never had a rust issue. In fact the one I used the most had zero signs of rust when I took the FSB off over a year later.
I would also take something like a bore snake, and put about 6 drops of oil near the copper brush part, and run it through the barrel a few times to hit up the gas port.
I don't ever recall seeing an L stamped on the barrel extension. The only barrel extensions Im aware of that have a stamp is Colt which has a 4 on the right side.
Blankwaffe
05-11-10, 23:22
The stamp/proof on the breech face of my LMT barrel looks like its supposed to be a star.
Learn somethng everyday ref the chamber marking. I picked up on the fsb pins as being LMT.
Now, concerning the fsb issue-this is me-
I always wipe down the barrel and fsb area with clp to keep it "seasoned" I also place a few drops around the fsb on the "topside" of the fsb(depending on which way you store it-muzzle up/down) This allows the clp to seep into and under it to keep that from occuring. Remember-never saw mamma's seasoned cast iron skillet with rust did you?;)
Blankwaffe
05-12-10, 05:00
Learn somethng everyday ref the chamber marking. I picked up on the fsb pins as being LMT.
Now, concerning the fsb issue-this is me-
I always wipe down the barrel and fsb area with clp to keep it "seasoned" I also place a few drops around the fsb on the "topside" of the fsb(depending on which way you store it-muzzle up/down) This allows the clp to seep into and under it to keep that from occuring. Remember-never saw mamma's seasoned cast iron skillet with rust did you?;)
Oh you would probably slap my hat off due to the film of oil I keep on the AR's.I just wear it off in use.But its due to the environment in which I find myself that will either rust or mildew stuff in short order.Especially here lately with the twelve or so inches of recent humidity.
And just for the record yall would be shocked at just how effective a christmas tree bag can be for hauling all your weapons in a pinch.
I appreciate the responses and information. As far as wiping the barrels down with oil to keep them seasoned on my guns, sometimes I do, sometimes I don't. It all depends on the environment they've been in (rain) or if I've handled the barrel a lot. If present, I always do it to remove fingerprints, etc.
My blued deer rifles usually get a coat of oil as they're prone to rust if you look at them funny. I'll be paying more attention to the FSB on the rifle in question (and every FSB) in the future.
Thanks again.
Here's my LMT Star stamp:
http://farm4.static.flickr.com/3300/4601411796_6fd9aefac0_b.jpg
So does LMT use different proof marks/stamps, or is mine just a shoddy attempt/example of the star?
Again, I have never seen this discussed here on M4C. The search function isn't great, but I did attempt it.
CTBuilder1
05-12-10, 10:20
So does LMT use different proof marks/stamps, or is mine just a shotty attempt/example of the star?
Again, I have never seen this discussed here on M4C. The search function isn't great, but I did attempt it.
Depends on how and where the stamp hits. My last LMT upper looked more like the pics on top of the page than the ones on the bottom. They all have at least some portion of the star stamp on them.
Littlelebowski
05-12-10, 10:23
I've seen it mentioned elsewhere on this site that the "goo" is actually a compound used in manufacturing and should be ignored.
both are common and don't affect function. some people have removed their gas blocks to address the rust problems. it would drive me crazy.
I've seen it mentioned elsewhere on this site that the "goo" is actually a compound used in manufacturing and should be ignored.
Roger. It is a bit distracting though. I think I'll just clean it up and check on it from time to time.
Blankwaffe
05-12-10, 21:34
Here's my LMT Star stamp:
http://farm4.static.flickr.com/3300/4601411796_6fd9aefac0_b.jpg
Nice one there.Mine only has the very top half of the star.
http://img.photobucket.com/albums/v214/kry226/LMT003.jpg
Is it me or do the feed ramps seem to not be lined up/polished correctly?
Riley~~~
Is it me or do the feed ramps seem to not be lined up/polished correctly?
Riley~~~
Yes, I too was thinking this. All I can say is that I believe this gun was built at the height of the post-Obama AR craze and done so with haste (which may explain the shoddy star/stamp on the breach face?). To this point, it hasn't been problematic, and I will leave well-enough alone until it is. The gun runs like a champ with both .223 and 5.56 and is smoother-cycling than any AR I have ever shot, and I doubt it will ever give me a moment's trouble for many years to come. But yes, one might expect a better alignment.
Have you run any HP or soft tip sounds through it yet? They may hang up on that edge... but its nothing that two minutes with a dremel can't solve.
Riley~~~
Have you run any HP or soft tip sounds through it yet? They may hang up on that edge... but its nothing that two minutes with a dremel can't solve.
Riley~~~
No, only FMJ. It's something I will definitely pay attention to though.
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