School me on QD muzzle device installation

[calebp]

Hey folks,

I have always used direct thread for cans in the past but have booked a flow 556k and would like to go ahead and throw QD flash hiders on everything so I can easily move it around until I get more dedicated 556 cans. Do I just screw the muzzle device onto the barrel and torque to proper ft/lbs or is a crush washer needed? I have also heard a drop or two of rocksett on the flash hider would be a good idea. Also, I’ve never used cocentricity rods in the past but have heard them highly recommended. Seems cheaper than blowing the internals out of a $1200 can. Do I use it every time I mount the can to a new rifle or just initially to confirm cocentricity? Any advice/opinions welcome.

Thanks!
Caleb

 

[alexs2006]

Cheap concentricity rods at McMaster Carr.

 

[erykv1]

never use a crush washer for suppressor applications. shims and spacers are ok.
you can torque and go for the most part (assuming you are using a quality barrel / muzzle device), but a some rocksett doesnt hurt to keep things where you want them during use.

 

[SpeedyR]

no crush washers. The rods from McMaster are good, check once you mount your flash hider/mount and can and then you should be good to go. shims are fine if you need to time a brake or something. Rockett or I use Vibratite HotLock on my muzzle devices is good insurance to make sure the muzzle devices stays on the barrel instead of stuck in the can.

 

[BigMike]

Shims if needed to time the device, I don't use thread locker on mine. 20 ft/lbs is more than most folks can twist by hand.

 

[cmshoot]

There’s a pretty good chance that your suppressor can become carbon-locked to your muzzle device, so I always recommend Rocksett. You go to remove your can, and your muzzle device comes off with it. That’s carbon-lock.

A regular service I do in the shop is to remove stuck muzzle devices from inside suppressors, so it is a not uncommon thing.

To do the job properly, you’ll need:

-something to degrease the threads on the barrel AND the muzzle device; denatured alcohol, acetone, non-chlorinated brake cleaner, etc.

-foot/pound torque wrench. I go with the manufacturer’s specs on what to torque the muzzle device to. If there aren’t any specs, and it’s a 5.56 with 1/2x28 threads, I go 18-20ft/lbs. Too much torque, and you can stretch the threaded section of the barrel, which will mess with your accuracy. Too little, and it may not stay in place.

-appropriate wrench to fit your muzzle device

-shims. I prefer to use the shims from Precision Armament. They are gradually thicker, so you only have to use one. I don’t like using more than one shim to time a muzzle device, and I haven’t done so in years. If you’re using something like 3 or 4 prong flash hiders, without some kinda compensating ports (FFS), then you do not need shims and you do not need to time/index the device. I use SilencerCo ASR 3-prong flash hiders, and I never shim them. Just raw dog it.

-Rocksett

-device to hold your barrel. If it’s an AR, I prefer to use reaction rods from Midwest Industries first, and Geissele second. If it’s a bolt action, or other non-AR rifle, I use nylon jaws in my vice that are made to grab round/tubular objects.

Do it:

1. If the muzzle device needs timed, experiment with your shims until you figure out which one you need to get it timed up properly when torqued.

2. Degrease the threads on the barrel, and inside the muzzle device. Make sure they’re dry. If the barrel and/or the MD are used, make sure there is no carbon on or in the threads. Soak and scrub them out if they do. I keep a tap and die set in my shop for chasing the threads when there is a lot of build-up, or old Rocksett/Loctite, on the threads.

3. Put a thin bead of Rocksett at 12 o’clock on the barrel. A little dab will do ya! If you put too much, the Rocksett can surface harden and stay gooey underneath. This is a failure, and you run the chance of having the device do an unscheduled disassembly on you. Here’s everything you need to know about installing and removing parts using Rocksett, from the company that invented it: https://cdn.shopify.com/s/files/1/0...60d84db4-0c98-40de-ab14-e4bf5cbd720c.pdf?2026

4. Torque the muzzle device down. Rocksett sets pretty fast, but I recommend folks to not shoot the firearm for 24 hours.

 

[BigMike]

There’s a pretty good chance that your suppressor can become carbon-locked to your muzzle device, so I always recommend Rocksett. You go to remove your can, and your muzzle device comes off with it. That’s carbon-lock.

A regular service I do in the shop is to remove stuck muzzle devices from inside suppressors, so it is a not uncommon thing.

To do the job properly, you’ll need:

-something to degrease the threads on the barrel AND the muzzle device; denatured alcohol, acetone, non-chlorinated brake cleaner, etc.

-foot/pound torque wrench. I go with the manufacturer’s specs on what to torque the muzzle device to. If there aren’t any specs, and it’s a 5.56 with 1/2x28 threads, I go 18-20ft/lbs. Too much torque, and you can stretch the threaded section of the barrel, which will mess with your accuracy. Too little, and it may not stay in place.

-appropriate wrench to fit your muzzle device

-shims. I prefer to use the shims from Precision Armament. They are gradually thicker, so you only have to use one. I don’t like using more than one shim to time a muzzle device, and I haven’t done so in years. If you’re using something like 3 or 4 prong flash hiders, without some kinda compensating ports (FFS), then you do not need shims and you do not need to time/index the device. I use SilencerCo ASR 3-prong flash hiders, and I never shim them. Just raw dog it.

-Rocksett

-device to hold your barrel. If it’s an AR, I prefer to use reaction rods from Midwest Industries first, and Geissele second. If it’s a bolt action, or other non-AR rifle, I use nylon jaws in my vice that are made to grab round/tubular objects.

Do it:

1. If the muzzle device needs timed, experiment with your shims until you figure out which one you need to get it timed up properly when torqued.

2. Degrease the threads on the barrel, and inside the muzzle device. Make sure they’re dry. If the barrel and/or the MD are used, make sure there is no carbon on or in the threads. Soak and scrub them out if they do. I keep a tap and die set in my shop for chasing the threads when there is a lot of build-up, or old Rocksett/Loctite, on the threads.

3. Put a thin bead of Rocksett at 12 o’clock on the barrel. A little dab will do ya! If you put too much, the Rocksett can surface harden and stay gooey underneath. This is a failure, and you run the chance of having the device do an unscheduled disassembly on you. Here’s everything you need to know about installing and removing parts using Rocksett, from the company that invented it: https://cdn.shopify.com/s/files/1/0...60d84db4-0c98-40de-ab14-e4bf5cbd720c.pdf?2026

4. Torque the muzzle device down. Rocksett sets pretty fast, but I recommend folks to not shoot the firearm for 24 hours.

I need to bring you one of mine to do. My rocksett is probably 7 years old.

 

[cmshoot]

I need to bring you one of mine to do. My rocksett is probably 7 years old.

Are you saying that you have an old bottle of Rocksett, or that you have a muzzle device that was installed with Rocksett about 7 years ago.

I’ve never heard of Rocksett degrading over time. Ain’t saying it can’t/doesn’t happen, but I’ve never heard of it.

If you’re going to bring a Rocksetted device to me for remove, contact me first. There is prep that I’d like you to do ahead of time…….like the day before.

 

[BigMike]

Are you saying that you have an old bottle of Rocksett, or that you have a muzzle device that was installed with Rocksett about 7 years ago.

I’ve never heard of Rocksett degrading over time. Ain’t saying it can’t/doesn’t happen, but I’ve never heard of it.

If you’re going to bring a Rocksetted device to me for remove, contact me first. There is prep that I’d like you to do ahead of time…….like the day before.

My Rockett is very old. It is my understanding it starts to go bad after it's opened. Am I mistaken?

 

[cmshoot]

My Rockett is very old. It is my understanding it starts to go bad after it's opened. Am I mistaken?

If it’s still liquid, it should be good to go. I keep a large bottle on my mention, that I use almost daily. It’s probably 2 years old now, with no issues so far.

We sell the 1oz bottles of Rocksett at TruPrep now.