Help: Rust/Damage on exterior of AR Barrel?

C

cdnskier

CGN Regular
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Hey everyone,

I purchased a used milspec LMT CQB MRP upper here on CGN.

I'm a newbie. I noticed that there is a bit of rust and flaking and some sort of white crud on the black finish on the barrel.

What do you recommend I do / use to clean it? Is this something to worry about? The seller claimed that there were less than 600 rounds through it.

Does it look okay?

Thanks very much for your help.

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Just clean it.
However, look at the hole where the pin that retains the gas block on the barrel is located. Would LMT have chamfered the ends of the hole in such a sloppy manner? Look at the chatter.
 
That looks like carbon buildup as Robert says. If you're handy, you can grab a taper punch and tap out the retaining pin (it should be tapered I think right to left) on the gas block to inspect it for any damage and also clean it up.
 
Looks like the orig owner just stuck it in the safe after their last session a couple years ago. Whatever lube is there looks dried up and sticky.

If it were mine, I would definitely be taking that gas block off and inspecting everything. I'm OCD like that.
 
Looks like maybe the gas block could be miss-aligned causing gas leakage that is resistible for those marks around the gas block
I'd take it off and realign it
 
CraigNConnor said:
Looks like maybe the gas block could be miss-aligned causing gas leakage that is resistible for those marks around the gas block
I'd take it off and realign it
Click to expand...

I think it's a sh!tty place to pin a gas block 'cause the locking pin on that side of the GB would tend to take up any play between the GB and barrel ie pull the GB's gas port side away from the barrel which is why all the carbon is on that side of the barrel.

I'd buy a clamp on or screw down gas block (or pinned if you have the jig or means to add it) that would pull the GB gas port tighter towards the barrel's gas port and make a tighter seal.
 
Does the rifle work properly? If yes, then leave the gas block alone.

The gas block to barrel fit is likely a bit loose but the carbon will build up and seal any spaces. You can clean the exterior areas but if you remove the block and clean underneath that carbon will just build up again.
 
CraigNConnor said:
Looks like maybe the gas block could be miss-aligned causing gas leakage that is resistible for those marks around the gas block
I'd take it off and realign it
Click to expand...

Will go back in the same spot due to its cross pin secured. Pin on the bottom would seal better. It would force the gas block down onto the barrel.
 
Suputin said:
Does the rifle work properly? If yes, then leave the gas block alone.

The gas block to barrel fit is likely a bit loose but the carbon will build up and seal any spaces. You can clean the exterior areas but if you remove the block and clean underneath that carbon will just build up again.
Click to expand...
I agree, however removing the block and reseating it with green loctite will help.
 
Wow. Hopefully you have a good jug of clp and some good scraping tools. I cannot believe Someone sold a gun dirty like that!?!? Rusty! No oil for shipping... shame on that seller. However it should clean up with some oil and elbow grease
 
Jerry Champagne said:
Wow. Hopefully you have a good jug of clp and some good scraping tools. I cannot believe Someone sold a gun dirty like that!?!? Rusty! No oil for shipping... shame on that seller. However it should clean up with some oil and elbow grease
Click to expand...

hey jerry are you coming up my way for this supposed 3 gun shoot at custer?
 
Jerry Champagne said:
Just got my form 6 in today. Not sure how long it takes. Can you confirm the DTG for that event
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i dunno man I was looking at the custer range site and theres not much information of a shoot, custer is just 40 minutes away from my house.

http://www.custersportsmensclub.com
3 gun calendar
http://www.custersportsmensclub.com/competitions/multi-gun/

they do list november 14 as a shoot, but not much indication what the course of fire is

anyway they are announcing severe thunderstorms for the lower fraser valley this weekend so maybe itll be cancelled. Custer also requires proof of a safety class uspsa, but maybe since youre nato military they'd wave that, not sure you'd have to call them to make sure

"
If you haven’t had a safety class for USPSA or Multigun at some time in the past you are required to complete a safety class before you shoot a match. If you have any doubts as to your requirements please call

Rick Naslund 360-303-9519 sti38@comcast.net

Safety classes can’t be done the day of the match."
 
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