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View Full Version : Muzzle Brake Removal


Joe226
04-07-2011, 5:34 PM
I just bought a used Bushmaster upper through my gunsmith with about 500 rounds through it. It has a muzzle brake on it(I think AK-74 type) that I can't get off. I asked my gunsmith if it was pinned and he said yes but he didn't seem very sure about it. It has a 16" barrel so I don't know why it would be pinned. I looked at it and can't see any sign of it being pinned.

So what do you guys think? I want to get the brake off so I can clean the muzzle of the barrel it looks pretty dirty. Are there any tricks to get these off besides shooting it and trying to take it off while it's hot?

http://i771.photobucket.com/albums/xx360/joe226700/DSC02969.jpg

$P-Ritch$
04-07-2011, 5:43 PM
Use the macro setting, usually a flower icon, to get a clearer close up picture.

If it is pinned and welded there should be a round hump in the thread area where the hole was drilled, a blind pin inserted and then welded over. It should be a little over an 1/8" in diameter.

How have you tried to remove the brake? Do you have a vise and proper action block to secure the upper? If not, removing may be difficult just because of a lack of proper tools. One last idea, I know my AAC brake came with a tube of rockset (red loctite). If something like that was used on your brake your will need to heat it up first to remove it.

hammerhands32
04-07-2011, 5:46 PM
I had an armalite upper with a muzzle brake. I destroyed the muzzle brake because it was pinned and welded over. It took alot of work and some rethreading when it was all said and done. If it is not pinned just heat it up with a propane torch and then muscle it off. *If you are lacking the right tools it is cheaper to take it to a gunsmith and have it removed.*

Edited- Beat me to it so what the guy above me said.

Joe226
04-07-2011, 5:52 PM
There is definitely no "hump" or any sign of it being pinned.

I have it secured with a vise and action block.

I don't want to damage it so I have tried covering it with a cloth and using a crescent wrench on the cutout part of the brake. I an get a good amount of leverage but I am just not sure about the breaking point of the brake.

By the way, thanks for the camera tip P-Ritch.:o

Joe226
04-07-2011, 5:54 PM
Do you think there would be discoloration as a result of the torch?

Any suggestions on what tool to take it off with?

hammerhands32
04-07-2011, 5:55 PM
Righty loosey, lefty tighty :p

Left handed threads on Bushmasters? My armalite and alot of others are 9/16 by 1/2 left handed threads. Not sure about bushmasters as I've never had one but they are most likely the same.

I hope I am not dumbing it down to far for you but I usually try to cover the basics first.

reagan8
04-07-2011, 6:01 PM
I recently swapped my A2 birdcage for a Levang, and it was very difficult to remove until I applied heat. I just borrowed my wife's hair dryer and heated it for about 3 minutes; then it came off with very little effort.

Joe226
04-07-2011, 6:03 PM
Righty loosey, lefty tighty :p

Left handed threads on Bushmasters? My armalite and alot of others are 9/16 by 1/2 left handed threads. Not sure about bushmasters as I've never had one but they are most likely the same.

I hope I am not dumbing it down to far for you but I usually try to cover the basics first.

Yeh, I am not sure if Bushmasters have left or right handed threads.:confused: Anybody know for sure? I think it's an older upper(5 years or more) if that makes a difference.

Joe226
04-07-2011, 6:06 PM
I recently swapped my A2 birdcage for a Levang, and it was very difficult to remove until I applied heat. I just borrowed my wife's hair dryer and heated it for about 3 minutes; then it came off with very little effort.

Interesting idea. I'll be back in about 3 1/2 minutes to tell you if it works for me.:D

Joe226
04-07-2011, 6:16 PM
I think that I got it to move about 1/16".

dieselpower
04-07-2011, 6:20 PM
You positively checked and know for sure the barrel is 16" long. meaning subtracting the length of the MD from a measurement taken from the muzzle to the closed bolt.

Ok, then you need to lock it in a vise, heat the MD with a torch and wrench it off.

Just to be sure... take a dremil tool and sand away at the whole threaded area of the MD...you may find its pinned and that is a sure way to find it.

AR-15 Rep
04-07-2011, 7:30 PM
Just a quick note... some years ago they used to silver solder muzzle breaks in place. That may not be the case here but no matter what you try, the best thing to do is lightly sand the bottom area of the break, and see if there was a pin welded in place. It may be in another area but typically most installed them on the bottom. The other thing is the silver crush washer? normally they are black so that may give away to the silver solder idea.

dieselpower
04-07-2011, 7:57 PM
My 14.5" was assembled before Silver solder was OKed by the ATF. I have a silver crush washer.

As AR-15 Rep and I have said, sand the bottom of that MD.

reagan8
04-07-2011, 8:33 PM
I think that I got it to move about 1/16".

If it moved after applying heat and didn't before, keep applying heat and try it again. If it was installed with locktite, you may have melted a few threads' worth on the first try. Keep going... nothing to lose (and a lot better than doing something more extreme that might not be necessary). If that doesn't work, then I humbly defer to the other posts.

Also, put the barrel in the vise as close to the brake as possible.

morfeeis
04-08-2011, 12:25 AM
I recently swapped my A2 birdcage for a Levang, and it was very difficult to remove until I applied heat. I just borrowed my wife's hair dryer and heated it for about 3 minutes; then it came off with very little effort.
Thats how i got my FH off too........