Kinda a rookie build question so I apologize. I saw some guy putting red loctite on the barrel extension prior to installing the barrel into the upper receiver. It didn’t look like an awesome idea to me but maybe I’m wrong bc I have always just kinda stuck the barrel in without any special products or anything. Does anyone here put anything on the barrel extension prior to install? Thanks
It’s called bedding and its been discussed here at great length.
Red Loctite isn’t the right choice.
If its of any benefit depends on the parts used, quality of the ammunition and the skill of the shooter. It won’t make a 2 MOA gun a 1/2 MOA one, but can perhaps influence a 3/4 MOA gun closer to a 1/2 MOA one.
Thanks… i apologize and look it up. I just didn’t know what it was called.
Don’t assemble anything with RED that you ever want to take apart without a torch! GH
Loctite on anything barrel related is a big no-no.
Use a none-lithium grease around the threads where the barrel nut screws on to, and tighten down between 30-50 foot pounds. Once that is done, untighten the barrel and repeat this process two more times before tightening down the barrel nut the last time, making sure the gas tube can be inserted unobstructed and does not touch the receiver or the barrel nut.
Not to highjack the thread, but what if you do not do that? I just applied grease, torqued to 30 foot pounds, then went to 50. I have heard of tightening and loosening the nut a couple times here, but I never recall as to why.
Does that ensure the barrel nut will not come loose?
Nothing. Some people are just anal. The barrel nut won’t loosen if you torqued it to the proper spec once. You’re not going to gain another tooth on the barrel nut by doing it three times.
Metal stretches as it is torqued. This is why it’s done three times.
Also, don’t use a blow torch to loosen Loctite parts, use a heat gun.
Why not use what the Mil-Spec calls for?
Www.ucwrg.com/materiel/weapon-lubrication/18/aeroshell-33ms-grease/
Just askin’…
Rascal
The reason for repeat torquing is so that the fastening system retains the set torque spec. Threaded fasteners are nothing more than helical wedges. As the mating surfaces of the two components slide across one another they “wear in”. The peaks on the surface finish are worn down with each torquing. Part of the resistance during torquing is the stretching of the metal. The other part is the friction of rotation. As the parts wear in, a larger portion of the resistance is the stretch and a smaller portion the friction. Torquing three times brings the stretch closer to the ideal fastening force.
Thanks, and thanks to everyone else.
So then, is it even worth the trouble to retorque it? Or should I be good? The barrel nut is not loose for the 500 rounds I put through this new rifle. The Daniel Defense directions only mentioned torquing to 50, so that is what I did.
Thanks for all of the good info… i have built several ARs with the help of a friend (used the moly grease but didn’t torque and re-torque) so this will be my first complete solo build and when i saw some ppl doing it different I just wanted to check because these builds get expensive and I want to do it correctly.
Once had to remove a red loctited fastener. The torch was the only thing that worked! Needless to say, i don’t particularly like red loctite 
When those guys are talking about using red loctite they are putting a few drops around the barrel extension and inserting it in the upper receiver, not on the threads. A bunch of heat from a heat gun and knock it out with a dowel if you need to replace it. Not that’d I’d bother to do it, but that’s the way I’ve read it being done.
The Loctite I would use, and did…is Loctite 609, which is typed as being a sleeve retainer compound.
Its green.
For what its worth, out of a Noveske Afghan, with limited load development the gun routinely shoots 3/4 MOA groups, with the best being .462"
Because it’s not in stock, and the Valvoline works well, too.
Why on Earth would people loctite the extension to the upper? Do they not trust their skills, or think they might want to take the barrel out?
I have no idea… i just wanted to get a visual reference for drilling dimples and next thing i know this dude is smearing red loctite all over his barrel extension. Check it out (5:37) http://www.youtube.com/watch?v=GtDNVru966g
I’ve got a JP Ent. free float hand guard that hasn’t been mounted yet.
The instruction set call for using RED Loc-tite on what is called a “outer receiver nut” where it threads onto the upper receiver forging.
This “nut” -doesn’t- by itself, hold the barrel on, but acts as a “thread converter” (outside-to-inside). It is explained that the “nut” could turn while torqueing the barrel nut and consequently looseing the line up of the gas tube channel between the receiver and the “nut”.
I have always looked at RED Loc-tite as a coarse and difficult substance to use, but, the folks at JP -ARE- leaders in thier field. The instructions go so far as to explain how to defeat the Loc-tite RED271 using a propane torch and a specific temperature.
I still consider it sort of scary, and will probably trade messages with the JP support folks before I spill the RED271 on my gun’s threads.
Lord knows, I’d certainly NEVER use it anywhere else that I ever contemplated needing to dismantle for kicks or giggles.
I don’t know that I have ever heard of red used on anything, but then again I have never built my own so this is some good information!
As to why someone would consider using the Loc-tite RED271 as a bedding compound, the JP instruction sheet says that the stuff will degrade to a “white powder when subjected to 400-450 degrees F.” .
I think that just might be beyond the temperature reached while extended/rapid fire of the rifle.
It also doesn’t shrink, and it is mighty tough when it has hardened, but…
The problem I’d see in using it for that purpose is that it sets up -or- hardens (in the short term, anyway) in an enviroment lacking in oxygen.
Sure it WILL dry out and fill gaps and such, but it takes a loonnnggg time when used in an enviroment other than it is intended for.