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:
Then found some rusty goo (gas leak) emerging from under the FSB:
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.
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.
Wow. No beef with logos, just never read or heard of them doing that. I guess that explains the sewing machine part.
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.
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.
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.
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.
