Loctite 620 and my silencerco muzzle brake

magman687

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Jul 14, 2010
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I feel like a fool it was recommended from LaRue Tactical use 620 on the LaRue Tactical stealth Barrel threads for my suppressor muzzle brake from silencerco.
I got it shimmed up to where I thought it should be and allowed a little bit of room for torque so I applied the 620 compound threaded the brake on about halfway turned around to get my foot pound foot pound ratchet which took less than 20 seconds and whenever I tried to turn the muzzle device it was very hard to turn and before I can make it to where the muzzle device was perfectly flush and even it was Rock Solid.
Loctite claimed they had a 60 minute set time but in my experience just now it was a 40-second set time.
With the shims I am just a smidge off from being level on the muzzle brake if you weren't paying attention you probably wouldn't even notice that it was a little crooked.
My concern is whether or not when I put my can on if it's going to cause a baffle strike in the end from being slightly off the center axis if the shoulder doesn't meet up with the muzzle brake well enough.
Not sure if I can just wait until I get my can out of jail and put it on and run a clean Rod up through the door and Center it the best I can in the back of my action and see if there's any run out or not.


I feel like im fine like there's enough contact between the 90° on the barrel the shims and the 90° on the muzzle brake but I'm anal about this kind of thing and I feel like I might be overthinking it LOL.


As a little side note I know it's making contact with the shims because I can't even budge them which is what leads me to believe they are probably making full contact with both 90° surfaces therefore leveling the muzzle brake to the bore.

I'm really thinking I should have just used the rock set that came with it now LOL.

It's been many many years since I posted here so hopefully you all are just as nice as you used to be and don't eat my ass up for this question thanks in advance and hope you all are having a great day
 
Only way to be sure is to check concentricity with an alignment rod just under the diameter of your bore. A cleaning rod won't cut it. You can get steel rods from McMaster Carr for pretty cheap. Personally, I'd heat the muzzle device with a propane torch for 30-60 seconds to melt the Loctite. Then you can spin it off with minimal effort and redo it. I don't see how it could fully cure in less than a minute. Even using a primer, it would take 10-20 minutes to cure. You certain the brake threaded on fully with no resistance before you applied the Loctite?
 
I had the same issue with red loctite. Now I put it on only about 1/2 the muzzle threads.

I would just heat it and start over.


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Thank you very much everyone this is the conclusion that I came to as well it's a brand new suppressor and I am terrified to take the chance on messing it up so tomorrow I am going to order a alignment rod because I'd rather be safe than sorry I mean I'd rather spend a $25 to $35 on a rod and mess up a suppressor LOL.

So luckily I'm off work tomorrow so I'm going to take the heat gun to it and see if I can melt it with that and if that doesn't work I do have a torch.
The old oxy acetylene torch should do the trick and yes that's a joke I'd never touch it with that I'm talking about a propane torch LOL.

As a side note I do have extra shims so I should be good there I'm thinking about instead of using the 620 Loctite that was recommended by LaRue I'm thinking about using the rock set that came with the muzzle device since it will give me a lot more working time.

Also as my first thread in many many years I'm glad to see the people here are still decent when the rest of the internet is going to hell LOL
 
Thank you very much everyone this is the conclusion that I came to as well it's a brand new suppressor and I am terrified to take the chance on messing it up so tomorrow I am going to order a alignment rod because I'd rather be safe than sorry I mean I'd rather spend a $25 to $35 on a rod and mess up a suppressor LOL.

So luckily I'm off work tomorrow so I'm going to take the heat gun to it and see if I can melt it with that and if that doesn't work I do have a torch.
The old oxy acetylene torch should do the trick and yes that's a joke I'd never touch it with that I'm talking about a propane torch LOL.

As a side note I do have extra shims so I should be good there I'm thinking about instead of using the 620 Loctite that was recommended by LaRue I'm thinking about using the rock set that came with the muzzle device since it will give me a lot more working time.

Also as my first thread in many many years I'm glad to see the people here are still decent when the rest of the internet is going to hell LOL
I use a propane torch. The thing I like about a torch is that I can heat the brake fast and get it off without heating the barrel as much. My attempts with a good commercial grade Steinel heat gun took more time and allowed the heat to tranfer in that time. The positive of using a heat gun is that you can set/limit the temperature.

With red 271, it always turns to caked powder an Is fairly easy to clean off the threads.
 
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I use a propane torch. The thing I like about a torch is that I can heat the brake fast and get it off without heating the barrel as much. My attempts with a good commercial grade Steinel heat gun took more time and allowed the heat to tranfer in that time. The positive of using a heat gun is that you can set/limit the temperature.

With red 271, it always turns to caked powder an Is fairly easy to clean off the threads.
My apologies I meant to get back with you gentlemen today I started off using a heat gun and then I decided the hell with it and use the torch and the muzzle device came off just like you said it would with ease it was like nothing was even on it.
Then I reinstalled one of my muzzle brakes with Roxette that came with the silencerco muzzle brake.

And then I did the same with my second gun and by time I got to my third gun I went to open up the little pack of rocks that came with it and it was a firm gel and I noticed the package had a small hole in it so it pretty much dried up LOL.

I used the 620 Loctite on that device but it's on an AR platform so I'm a little concerned about the Heat I fire slow but in a shit hit the fan scenario I may need to fire rapidly.

I have Vibra tight hot lock but I'm afraid to use it on my LaRue Barrel because I heard a horror story of a guy that used it and it didn't play nicely with the metal they use on their barrels and pretty much disintegrated his threads.
When I contacted LaRue about it to see if it was true they said that they don't recommend hot lock for their barrels but apparently they use 620 Loctite whenever they send out their rifles that have quick detached muzzle devices on them.
So I figured it's good enough for LaRue it's probably good enough for me but I still have my concerns about it getting too hot for the 620 Loctite that claims it only goes up to 450°, but I believe it weakens to about 50% strength at 300°.

So I'm probably going to get some more rock set just to play it safe thanks to you all I'm no longer intimidated by 6:20 Loctite now that I know how easily it comes off with heat LOL.

My apologies for the long-winded text also I like to be thorough when I do something I'm that type of guy that you can give me one simple task and I asked a million questions about it because I want to make sure it's perfect I'm very anal about my firearms.
 
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You have to shake the piss out of new bottles of 620, it will separate/settle. I shook it a few seconds by hand and I had the opposite issue with 620, it didn't want to cure properly. Cleaned everything up, put the 620 in a paint shaker and let it go, spun the bottle and did it again. When I installed the barrel in the receiver the 2nd time, it was locked in place an hour later. It hasn't moved in several years and 1000s of rounds.
 
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You have to shake the piss out of new bottles of 620, it will separate/settle. I shook it a few seconds by hand and I had the opposite issue with 620, it didn't want to cure properly. Cleaned everything up, put the 620 in a paint shaker and let it go, spun the bottle and did it again. When I installed the barrel in the receiver the 2nd time, it was locked in place an hour later. It hasn't moved in several years and 1000s of rounds.
The odd thing is when I was installing it and it started to cure within 20 seconds to the point it was extremely difficult to get on and it locked up before I technically even got it to meet perfectly flush with the 90° shoulder of the barrel but yesterday when I redid it 20 minutes later I could still move the muscle device so I'm wondering if it's the fact that the LaRue Barrel is made out of stainless steel and I'm not sure what the Savage 110 tactical Barrel is made of but it cured fast to it
 
I’ve seen some mental masturbation in my time but damn this takes the cake.
Lol me or holliday.
And is mental masturbation a compliment or an insult forgive me I've never heard the term.

Also just to clarify if it was meant as an insult I'm sure it was meant as friendly banter which is how I would take itlol
 
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Glad you got it "right", would've been simple enough to try to slide a .001 shim between the device and the shoulder to see if you made contact which would be enough to make correct shoulder alignment. If you were as close as you say, probably just thread crush after contact to get it perfectly clocked.

I've installed a gazillion brakes (granted- alignment isn't as critical as a can) on skinny .30 cals where I didn't have enough shoulder for me to be comfortable torquing the bejeezus out of it. I'd cut the shoulder to the point where the brake would make decent contact without risk of distorting it with too much torque, and Rocksett or red loctite in place to make sure it couldn't vibrate loose.
 
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Glad you got it "right", would've been simple enough to try to slide a .001 shim between the device and the shoulder to see if you made contact which would be enough to make correct shoulder alignment. If you were as close as you say, probably just thread crush after contact to get it perfectly clocked.

I've installed a gazillion brakes (granted- alignment isn't as critical as a can) on skinny .30 cals where I didn't have enough shoulder for me to be comfortable torquing the bejeezus out of it. I'd cut the shoulder to the point where the brake would make decent contact without risk of distorting it with too much torque, and Rocksett or red loctite in place to make sure it couldn't vibrate loose.
The shims were large enough that there were portions of it sticking out and I couldn't move them so I felt like they were probably making contact and being squished however I overthink things a lot and in my head I was also thinking since that 620 cured so quickly that it was possible that they were actually just stuck because of the 620 Loctite and not because they were being squished.

This is my first can and they are expensive Investments so I'm just really wanting to make sure I have everything as close to perfect as I can get so I don't get baffle strikes or things of that nature.

For example I know the silencer Co muscle device said to use 20-30 ft lb of torque but in order to get mine to clock properly I had to go to about 38 ft lb and now that keeps bouncing around in my head because I'm a stickler for accuracy and I know over twerking a muzzle device can cause accuracy issues.

With good ammo I'm getting pretty regularly under half inch five shot groups measured Center to Center with several beam below 0.4 and a few of them being down in the 0.1 0.2 range out of my LaRue Tactical upper with 69 grain Sierra match Kings.

So like I stated above I get in my own head way too much whenever it comes to this stuff.

I had it shimmed up to where it was clocked correctly with 16 ft lb of torque but even the smallest shim after that brought it to where it required the 38 ft pounds I mentioned above and for safety reasons I guess I'd rather be a little over torqued than under torqued.
Especially since this is a firearm I use for my job and the last thing you want is your muzzle brake backing off in the middle of a firefight LOL.