Blue Residue on Crown/Flash Hider Area of AR-15

[Evergreen]

Hi, I have not done much rifle shooting in a couple years and my ARs have been sitting in my safe and collecting dust. I know some people say if you do not shoot them for a while, you should lube the barrels to prevent rust. Well, I have a safe with a dehumidifier, but I don't keep the safe open a lot and my guns just sit there.

Well, I am not sure if I am paranoid, but I have an LMT AR-15 that has some blue residue around the crown of the barrel/inside the bottom part of the flash hider that connects to the barrels. The flash hider is fixed, so I have no way of removing it. My worst fears are that it is corrosion or rust of some sort. I tried cleaning out the gun again and the barrel is shiny, so the blue gunk seems to be in an area I cannot clean. I probably did something I should not do, but I tried running some wet and dry patches through the crown of the gun and I did manage to get some of the blue gunk off, but not all of it. I then started poking cloth with a cleaning rod to see if I could clean the hidden crevices of the area. I did see some blue color junk come off on the rag, but no matter how hard I try, the blue sticky-looking residue is present on the crown area of the gun.

I am wondering if anyone can tell me what they think this blue residue is, whether it be just powder residue, solvent residue or, which I pray not, corrosion of some sort. Also, does anyone think I could have messed up the barrel or crown of the gun by poking my carbon fiber rod inside it to try to clean it? I also tried scrubbing the inside a bit with a nylon brush and ran a couple wet patches, then couple dry patches form the crown to the breech.

I'd appreciate any input people can give me. I am rather inexperienced with rifle maintenance, as I don't get much time to shoot them. I am thinking about having all my rifles checked out by a gunsmith to make sure there hasn't been any damage s from the long-term safe storage. I am thinking I am going to limit my shooting rifles to just 1 or 2 and see about storing my other rifles for the long term.

 

[madcratebuilder]

Sounds like powder residue to me. Try a tooth brush with some Hoppe's No 9 solvent. Your safe with dehumidifier sounds like you have storage under control.

I recommend you use a product called Eezox as a metal treatment against rust and corrosion. It dries leaving no oily film. I maintain over a hundred long guns and pistols and Eezox is the best rust preventive I've ever used. From Match locks to AR's it gets it done.

 

[briansmithwins]

I recommend you use a product called Eezox as a metal treatment against rust and corrosion. It dries leaving no oily film. I maintain over a hundred long guns and pistols and Eezox is the best rust preventive I've ever used. From Match locks to AR's it gets it done.

If you can take the smell. Eezox always reminds me of a chemical lab where they deal with nasty stuff.

The blue residue is most likely copper fouling that your solvent has removed. I've seen it before and don't worry about it too much. Never caused any long term problems either.

You're more likely to damage the rifle by scraping it to remove all traces of fouling than that fouling is going to cause any corrosion.

BSW

 

[Z-Michigan]

Madcratebuilder, I like Eezox but I absolutely minimize my use of it because of the TCE content. Not good for you. I mostly use Boeshield as a preservative and recently SLIP2000 EWL to lubricate things that need to still be slick when they are dry. Basically I use Eezox just to preserve items where I can't stand the slight waxiness that remains when using Boeshield.

 

[Evergreen]

Thanks for this information... I hope I didn't cause any damage to the crown area by trying to remove this stuff. I guess I should have waited to try cleaning it before I asked some questions here about it. I haven't taken the gun shooting in a long time, so maybe after I do, would some of this residue would burn away?

 

[rcmodel]

Black or gray is powder residue.

Blue or green is copper jacket fouling.

If you have it on the muzzle, you likely have it in the bore too.

Suggest a good scrubbing with any of the name brand Copper Solvents to get-R-done.
Regular powder solvent won't take it out.

rc

 

[Evergreen]

Hi rc.. I have cleaned the bore pretty well and I cannot find any trace of blue or green. IT seems all concentrated on the muzzle area inside the base of the flash hider. When I attempted to clean around the muzzle is when my cloths picked up the blue residue. Do you think cleaning from crown to the breech is a bad idea? I have been attempting to clean from the muzzle, but I am afraid I might cause damage to the barrel by doing this. I don't realy know how I can get any solvent in the area I am mentioning, as the area seems to be sensitive and I was afraid to use a brass brush around the muzzle. Because, the flash hider is fixed onto the barrel, it is hard for me to clean this area just by wiping it with a cloth.

 

[Z-Michigan]

You say the flash hider is fixed - are you in a ban state, or is this a 14.5" barrel with a permanent something to make it a legal 16"? Unless you answer yes to one of those two, it will come off easily with a 5/8" wrench, although removal of the flash hider is definitely NOT a routine maintenance item.

Anyway, an A2 flash hider is a $6-8 part, and even if it were going to corrode into dust - which it absolutely will not - I wouldn't sweat it, since you shouldn't take a risk damaging the much more important >$200 barrel it is mounted on.

I have an Armalite with a perma-brake that I've had for about 6 years, and it's had some grayish-green discoloration inside the brake since I first started using it. Doesn't hurt anything, and it doesn't result in any visible corrosion. This just isn't worth any time or effort worrying about, much less trying to clean off.

 

[Evergreen]

Thanks Michigan for your advice and information, once again.. I guess I should have just left it alone and not mess with trying to clean it.. Now, I am worried I may have screwed up the barrel or the fragile crown area of the barrel. Anyway, for now on, I will know not to mess with this and accept that this residue is a not anything dire to worry about. I guess I've never seen it before, so I was a bit worried. Also, I have been worried about the long term storage of my guns. SOmeone told me it's best to leave your safe door open during the day to help air circulate in your safe better. I am thinking I will try to do that. Sadly, my safe is not near me, so I don't always have the opportunity to do that.

 

[Z-Michigan]

I guess I've never seen it before, so I was a bit worried.

Oh I understand. Many things with AR15s are different from more classical (dare I say old? The AR itself is around 50!) designs. Like the fact that carbon builds up in some nooks and crannies where it looks ugly but does no harm, has no effect on function, and isn't worth any effort to remove.

Also, I have been worried about the long term storage of my guns. SOmeone told me it's best to leave your safe door open during the day to help air circulate in your safe better. I am thinking I will try to do that. Sadly, my safe is not near me, so I don't always have the opportunity to do that.

Uh, no, I haven't heard that one before. What's the security level like when the safe door is open? Get a simple silica gel desiccant sized for your safe, put it in there, don't open the door more than you need to, and recharge the desiccant when it turns pink, and all will be fine. Remington sells a really handy $25 desiccant that has a built in heater and plug so when it's wet you simply plug it into a wall outlet for half a day and it's recharged and ready to use again. Very little effort, not much cost.

 

[rcmodel]

I don't realy know how I can get any solvent in the area I am mentioning, as the area seems to be sensitive and I was afraid to use a brass brush around the muzzle.

Use a small model paint brush to dab solvent in there.

Use a wood or bamboo meat skewer stick to scrape around on it.

You simply cannot harm the crown with either one.

A brass brush cannot harm the crown either.
Barrel steel is a lot harder then any brass brush ever thought about being.

Always take the bolt out and clean from the chamber end.
Never from the muzzle.
Tiy simply cannot harm the crown cleaning from the breech end of the barrel either.

rc

 

[Evergreen]

Always take the bolt out and clean from the chamber end.
Never from the muzzle.
Tiy simply cannot harm the crown cleaning from the breech end of the barrel either.

I did try cleaning the gun from the muzzle end a few times.. I did this because I thought it would help remove some of the blue residue at the time, although it didn't. Do you think doing this a few times could have damaged the crown? I've never attempted to do what I did before, going from muzzle to breech, although I have cleaned my Saiga this way. I feel kinda stupid for doing this and hope I didn't cause any damage.

Thanks for the advice about the paintbrush and skewer, I think I will give that a try. It would be nice to get the area cleaned up if I know I can do it safely.

I just hope I didn't cause any damage in my previous attempts. It's been so long since I have dealt with my rifles, I feel so stupid about all this.

 

[Z-Michigan]

It's extremely unlikely that you damaged the crown with the cleaning attempts you described.