I am going to rebarrel my AR for the first time. My question is in reference to the lube you must place on the reciever threads and barrel nut when torquing it down to spec.
Army TM recommends "Molybdenum disulfide"
E.P. Anti-seize engine assembly lube with moly and graphite.
This is what is says on the back:
Sta-Lube engine assembly lube provides protecytion from scoring, galling and seizing during the installation and assembly of parts.
This specially formulated 12 hydroxy lithium base compound contains molybdenum disulfide, high purity allotropic graphite, tackiness agents, thermosplastic polymers, anti-rust and anti-corrosive agents disperesd in a high viscosity oil.
* Adhears tightly to engine parts
* Helps prevent metal to metal contact
* Cushions close fitting surfaces
* Protects against rust and corrosion
* Will not clog oil passages
* Soft consistency for ease in application
Contains: Mineral Oil (heavy), Lithium Soap, Calcium Dinoyinaphthalene Suflonate, Zinc Dithiophosphate.
Recommended For: Engine, transmission and differential assembly.
Use on: camshaft bearings and lobes, crankshafts, engine bearings, gears, lifters, push rods, valve stems and all areas of rotational or sliding metal to metal contact.
So is this okay to use on an aluminum receiver? I dont want to damage anything since this will be my first time.
That lube should work fine. Make sure all of the mating surfaces are clean.
If you torque, loosen, torque, loosen several times before final torque, it will ensure that everything seats well and will help establish the proper barrel index and sight alignment.
Don't get hung up on what to use on the barrel nut. More AR-15 voodoo. Any good anti-sieze or assembly lube that will not attack the aluminum or its anodized coating will do fine. The real worry is doing it dry as the torque may not be true due to drag on the parts or just plain galling of the aluminum by the steel nut.
Thanks for the replies.
Now how do I know if what I have will attack the aluminum or the anodizing? It doesnt say on the tube at all.
Any ideas based off the above? Maybe I should just buy a tube of that anti-seizing thread lube for spark plugs. At least that says its for use on aluminum engine blocks.
What you have should work great. While I have never assembled an AR upper, I have assembled hundreds of aluminum motorcycle engines with what you have.None ever grenaded.
The key is, dont use a ton of it. The torquing advice earlier is also good but I might add: dont apply full torque on the first go. Do it in stages. Then loosen it and re-torque. Re-check torque after 50-100 rounds.Also THE most important thing about torquing anything is: when you reach the specified torque, the wrench must be moving. What I mean is: it takes some extra torque to get the wrench moving. You will only read a true spec if the wrench is actually moving when you read it. This applies for both click and pointer type wrenches.
When you apply the stuff, a very thin coat is all thats needed.