Muzzle brake installation

[lamrith]

Hey all,
I am continuing to enjoy my Grendel, put another 20rnds thru it yesterday dialing in new scope and mounts. I was less than stable so had to pull the sandbags out after 5 rounds being all over and seeming to not respond to turret adjustments..

Ended the day with a decent 5 round group, was .527MOA until I jerked the last shot (always the case!!)


Now for my question. I noticed a few shots the gun jumped left a little, then putting the gun away I saw that my brake had loosened by about 1/8 a turn. I have a Killer Innovations brake.

How do you guys install your brakes, a certain torque? a drop of locktight? I am concerned about torquing it to much as I have heard that can distort the barrel/rifling.

[NugginFutz]

lamrith,

Each muzzle brake has its own method of torquing - crush washer, split washer, lock nut, etc. I am not sure about the Killer Innovations. If it uses a lock nut, it's straightforward - use a backing wrench to hold the brake aligned and steady while tightening the lock nut. The other methods require a fixture to hold the barrel from torquing against the upper receiver while tightening the brake. At least that is the theory. Most people here will agree that you do not want to tighten the brakes against the barrel nut, and I am among them. A lot of guys do it anyway, and often get away with it, but there's always the risk of damaging the upper or torquing the barrel loose from the barrel extension.

The point is this: Correctly done, a muzzle device which requires a compression washer needs to be tightened with the aid of a barrel vice of some type.

I do NOT recommend using any thread lock or super glue on the muzzle threads, as I believe that it can come back and bite you if/when you remove the brake. If you feel compelled to use it because the brake won't stay tight, then I suggest LocTite Blue. If that occurs, though, I would suggest that it is for lack of a proper washer or lock nut.


ETA: Klem beat me to it - I forgot he is usually up at this time!

[Klem]

+1

Hmm yes...the 'Night' shift. That reminds me, 1.30pm, I'm off to the shops!

[lamrith]

Thanks guys! This brake did not come with any washer or lock nut.

I will check around and see if there is a shop that does not want a silly amount of $ to put the brake on and take 2 weeks.

[LRRPF52]

I'm leaning to the zero torque approach more nowadays. Once you've settled on a brake and are happy with it, many reputable companies are recommending to thread lock it with Red Loc-tite or Rocksett. Both of those have considerations for removal that you will need to be aware of if and when that time comes.

[lamrith]

Yeah Red locktight is a real bugger, we use it here at work for certain things. Pretty much have to blue wrench to get it to release though and not sure how I feel about heating up my barrel/brake that much if I have to remove it. My brake will not time in against the shoulder currently without spacers either which is why I have some in there now. might be nice to see if a gunsmith has better shims though mine are big and don't look good with larger OD than the brake.

[LRRPF52]

One brake that alleviates this is the Seekins ATC, with a knurled ring that abuts to the rear of the brake. It's an extremely effective brake too.

[lamrith]

Already have the Killer innovations. Installed myself, Worked great, just that it loosened up. Will see what I can find for local gunsmith.

[Klem]

A standard Milspec crush washer will work on your brake without the need for spacers or glue. $2.50


Again, you will need to isolate the barrel to protect it when you crank it up to time the brake. The cheapest option is a pair of barrel vise clamps. Like this setup;


Brownels sells their version for under $30. http://www.brownells.com/gunsmith-to...prod12470.aspx

If you are going to have three uppers (your avatar information) then a barrel vise or clamps is essential for building and servicing. Not just for brakes, for barrel nuts and gas blocks as well.

Truth be known the cheapest option is to get two blocks of wood and drill carefully down the join to make your own set of clamps. If you get the diameter of the hole close to the barrels' OD then the wood will nicely form around steel as you crank up the vise. I've done a bit of work on DIY diving torches in my time and we tend to glue them up something fierce to defeat salt water under pressure. Clamping the diameter and not the tangent is the only way you can get them loose. The same principle will work on your barrel.

[lamrith]

Thanks Klem!
I have a Std type washer, but the brake it not properly timed with just it in place. I do have grinder and lapping tables at work though, so I could always remove a little at a time until it times in correctly.. hrmmm Thanks for the wood idea, I have some I can use for sure.

[Klem]

Mate, compare the effort of shaving down a flat washer with spending $2.50 on a 1/2" crush washer. No contest.

Forgive me if you know this already but a crush washer is designed to compress at least a full 360degree turn of your muzzle device. The washer is hollow and gets crushed as you do it up until the brake is timed at the right spot. The compressed washer then provides enough friction so that it won't come loose during use. The military use them to time the brakes on their M4's.

[NugginFutz]

^^^ This!

I keep one or two of these in my parts bin.

[lamrith]

It is not a flat washer, I have what is supposed to be a crush washer, concave shaped but thick that came with my thread protector. I will admit I did not realize they were supposed to be able to crush that much though! I am assuming it just flatten the concaveness out as needed, acts like a disk spring to provide tension/friction?


However it is so hard that were I to try and tighten it to line up I am concerned I would damage the brake, or threads. Also having read on another forum about barrels with "trumpeted" and distorted rifling at the crown from threading or over tightening of muzzle devices I am erroring on the side of caution.

I will get some wood drilled to make a barrel clamp as you mentioned and see what clamping force that provides and try to tighten a bit more.

[ricsmall]

Lamrith

If the pm I sent u seems like too much work or hassle, order a set of stainless shims or peel washers from brownells and it'll make it easier. I like to have very little torque on end of barrel and rely on the blue loctite to hold brake on. Be sure to degrease threads with a good solvent and it will hold. Good luck

Richard

[lamrith]

I do have some shims I think I got from Brownells, they are large OD, bigger than the brake which I found funny. You all have given me a number of ideas I will be trying the next few days. THANKS!