Any here ever tried gluing their barrel extension into the receiver with Loctite?
Why would someone want to do that?
I will use locktite on the barrel extension on a target/long range rifle. I will not do it with a standard rifle. I like to take my hard use rifles apart once in a while to clean them up thoroughly so I won’t use locktite. If you get a quality receiver that you have to heat up to get the barrel in then locktite may not be necessary.
I do it on precision builds
Ummmm, no. A properly fitted and lapped barrel extension fit in the receiver would be more important for accuracy than “gluing” them together. The loctite will most likely break down under the heat of firing anyway, so why bother?
Any reason why? What color? If everything is in spec, and the BN is properly torqued, why is loctite needed for anything other than filling in the gaps between the upper and extension?
You’re essentially bedding the barrel to the receiver. Here is a good thread on the topic - https://www.m4carbine.net/showthread.php?119904-Applying-loctite-to-increase-accuracy
I just read through that thread, and it didn’t exactly illuminate anything in regards to the efficacy of using loctite.
I tend to agree with this notion…but I guess the phrase “how can it hurt” comes into play here. Other than difficulty removing your barrel from your upper, what are the drawbacks?
One note on this, after removing my White Oak barrel from a WOA factory upper, I noticed that they used red loctite and it was a PIA to remove. I’m rebuilding my precision upper using a billet upper, but I’m not going to use loctite (only anti-sieze grease) when assembling everything back together.
Drawback I can think of is precisely what you stated: not being able to separate the barrel from the upper if/when it is desired to do so. Deep cleaning? Barrel replacement?
Not to mention the unknowns of having a chemical inside your upper which isn’t designed for the heat loads its experiencing there.
What makes you think you wouldn’t be able to take them apart?
Applying a heat gun to the parts will make them easily removable. There is no permanent loctite.
That being said, red loctite isn’t what I would use, but rather the sleeve retaining versions which are typically green. I think its 607. Its not going to make a 3 MOA gun a 1/2 MOA one. But, you might make your 3/4 MOA rifle more consistent across different tempratures or take that 3/4 MOA and maybe make it a 5/8 MOA.
If its not a rifle I’m going to shoot for groups, I wouldn’t bother.
So just for clarification, you are stating that using loctite will help improve accuracy from 3/4 MOA to 5/8? And this is based on what exactly?
really I have been reading a lot about it. Looks like a lot of the precision upper builders are doing it.
Well since I am third in the MOA thread and I did it to my gun today we will see if it can take a 3/4 MOA gun and make it better. Same ammo next weekend with a glued barrel.
Looks like a good experiment.
Same here when I get my 20" WOA put back together…I just need to find an upper!
I would first direct you to my use of the word maybe…which wasn’t an accident.
I have noticed that in the last two uppers I’ve put together when I bedded things that they were more consistent. Not necessarily more accurate, but across all recorded groups there was less deviation. A dropping of “flyers” as it were.
I think that using a quality, tight-fitting upper receiver, such as the BCM4, would do more good than using Loctite.
Don’t get me wrong. I completely agree that a tight fitting upper is the most ideal solution. Not wanting to completely jerk BCM off, they only have a say in half of the equation. The barrel extension also has an effect here. So unless you are in a position to test fit many different parts to find the most ideal fit, bedding is just a tool to have in your back pocket should you find that your purchased parts aren’t quite ideal.
Permatex 640 is good to 400F - Mil-R-46082B Type II - static sheer at 300F - 1500psi
Loctite 609 is good to 300F - Mil-R-46082B Type I - static sheer at 300F - 1000psi
Both met Mil-R-46082B which requires -65 to 300F temp range.
The normal clearance filling ability of the retaining compounds is as follows: Type I -.004 inch, (,0.102mm) Type II -.008 inch (0.203mm). For optimum strength and cure, the clearance should not exceed .002 inch (0.058mm). (From the Mil-Spec)
Diameter of the hole in the upper: 1.000" +.002"
Diameter of barrel extension: .9987" -.0008"
Clearance: between .0013" and .0041"
Should be good enough to hold fairly well…especially since you really don’t care if you get maximum strength.
Thanks for that info - I think I’ll give it a try.
yep
I Disassembled my upper. degreased the barrel extension and inside of the receiver with brake cleaner. put a nice coat of red 271 Loctite on the receiver extension. Slid her home and cleaned up my overruns. screwed on the barrel nut to 35# of torque. took the assembly off the reaction rod and with qtips cleaned up the excess on the inside of the receiver/barrel extension. got it standing in a corner with the receiver up. Will let it dry till Friday.
last weekend I shot the MOA challenge before gluing in the barrel. That is pretty much what this gun averages. I am in third place. This Saturday I will use the same bullet and load and shoot the challenge again. We will see if there is any improvement.
Who believes there will be improvement? not?