AR15.Com Archives
 How do you get the pinned/welded muzzle brake off?
Cam-Pin  [Member]
8/1/2005 10:07:42 PM
After seeing so many pix of the cool muzzle attachments on this forum, I will now take the plunge and remove the Armalite pinned-welded on muzzle brake.

Can anyone direct me to the discussion threads on how to do this?

Thanks!
Spade  [Member]
8/1/2005 10:54:40 PM
Safest bet would probably be to call up ADCO (Industry Section) and have them do it.
Cableman  [Member]
8/2/2005 1:06:22 AM
I used my dremel and a high speed cutting bit.
Went slow and ground down to the pin.

Took the pin out and off came the old brake.

Bought a die to chase the threads.
Chased the threads and spun on a A2 FH from Armalite.

Worked great.

Cam-Pin  [Member]
8/2/2005 10:14:20 AM
Cableman:

The weld and pin are clearly visible so I will take a go with the Dremel.

A few questions before I start:

1. How does the pin engage the barrel? Does it go straight into a hole like a gas port, or sideways into a groove like a front sight base taper pin?

2. What happens to the threads when the pin and weld are removed?

Thanks
sniperx  [Dealer]
8/2/2005 10:23:02 AM
The pin goes across the threads. You will loose only a small part of a couple of threads if you are
careful. You can then carefully unthread the brake. If it acts like the thread is getting tight, stop
and spit the brake per below link. I usually just machine them off in a lathe.



www.quarterbore.net/forums/showthread.php?t=153
Cam-Pin  [Member]
8/2/2005 3:55:55 PM
SniperX:

What size thread is at the muzzle? After reading the link, I want to chase the threads with a die before putting something else on.

Thanks
sniperx  [Dealer]
8/2/2005 4:15:21 PM
5/8-24



If you do it carefully, you will not have to chase them. Maybe clean up a spot or two with a triangle
file. Using a die nut may make the threads looser, unless you get the right one (2B class)
uglygun  [Member]
8/2/2005 6:51:53 PM
My pin went across the threads differently, it actually struck a chord across the entire threads. In the pics at Quarterbore's site you can see it ends abruptly midway through it's contact with the threads.

I had some pictures of both my brake and my threads as they appeared on my gun but they are gone and no longer being hosted.

I can take some more pictures to show what I'm referring to, will take a day or two to get them up.

Looking at the weld spot on the bottom of the brake, you'd have no idea that the pin was placed in the brake such that it would cust across the threads. Looking at the brake from the muzzle end of the rifle, the pin went across the threads from the 6 o'clock position towards the 9 o'clock position with the entire pin bearing against the barrel.

I used a bench grinder to take my muzzle brake's diameter down while being VERY careful to watch for the outlines of the pin as I ground it down, it started to change from a more rounded shape to a much more eliptical shape as I ground material down, that instantly told me the pin was inserted against the threads but it didn't tell me what direction I had to grind to fully release the pin. Once I exposed both sides of the pin, I drove it loose with a punch. I spun the muzzle brake off and then chased the threads with a 5/8x24 hex die that cut a nice set of threads for putting my Vortex on.
Cam-Pin  [Member]
8/3/2005 3:29:50 PM
Uglygun:

Please post your pictures. It would help a great deal, especially since your brake was pinned differently than on the link from SniperX. After reading your description, I had a few questions:

1. If the pin cuts clear across the threads, rather than just to the centerline as on the SniperX link, what is holding the other non-welded end of the pin? Does it end in a blind hole?

2. Is the pin hardened? Can it be milled out instead of ground off?

Thanks
avengeusa  [Dealer]
8/3/2005 3:37:46 PM
a lathe works beautifully
Slash  [Team Member]
8/3/2005 4:18:36 PM

Originally Posted By Cam-Pin:
1. If the pin cuts clear across the threads, rather than just to the centerline as on the SniperX link, what is holding the other non-welded end of the pin? Does it end in a blind hole?

2. Is the pin hardened? Can it be milled out instead of ground off?

Thanks




1. It runs on a chord to the barrel, and is a blind hole.

2. Not hardened, porbably could be milled, but a lathe works best.



sniperx  [Dealer]
8/3/2005 4:32:04 PM

Originally Posted By Slash:

Originally Posted By Cam-Pin:
1. If the pin cuts clear across the threads, rather than just to the centerline as on the SniperX link, what is holding the other non-welded end of the pin? Does it end in a blind hole?

2. Is the pin hardened? Can it be milled out instead of ground off?

Thanks




1. It runs on a chord to the barrel, and is a blind hole.

2. Not hardened, porbably could be milled, but a lathe works best.







+1 on the lathe, though it can be milled, but takes longer. By milling it out you can save the brake.
I have been milling the pin out of all the Bushmasters I have been doing, simply because the pin
goes straight in on them and I can save the brake/FS. You can measure the outside diameter and
subtarct the 5/8 thread diameter and go an extra .04 to get below the thread just slightly. It makes a nice clean up spot. (Don't forget to divide the results of the diameters by two (2) so
you will know the depth)

O.D. of brake - .625 + .040= depth
2


TOM64  [Member]
8/4/2005 8:04:34 AM
I got my brake off last night by just grinding the weld at 6:00 up to 9:00 where I could see a dimple that I thought was the end of the blind hole. The best part was finding out it was already threaded, Armalite said it was pressed on.

BTW sniperx, the hardwood blocks worked perfect to get the barrel nut loose, my AR-10 project is now complete, Thanks.
sniperx  [Dealer]
8/4/2005 9:31:08 AM

Originally Posted By TOM64:
I got my brake off last night by just grinding the weld at 6:00 up to 9:00 where I could see a dimple that I thought was the end of the blind hole. The best part was finding out it was already threaded, Armalite said it was pressed on.

BTW sniperx, the hardwood blocks worked perfect to get the barrel nut loose, my AR-10 project is now complete, Thanks.




I am glad you got your 10 fixed up.


FYI The brakes that are pinned and welded have threaded barrels.
The brakes that have two pins in the bottom are pressed on.
The ones that are pressed on you are much better off machining them of in a lathe
or doing the split job. They are about .005 tight plus are on a knurled surface. Once removed
the barrel can be turned down and threaded. You can not just run a die nut over it as the diameter is over sized.


TOM64  [Member]
8/4/2005 11:13:05 AM

Originally Posted By sniperx:

Originally Posted By TOM64:
I got my brake off last night by just grinding the weld at 6:00 up to 9:00 where I could see a dimple that I thought was the end of the blind hole. The best part was finding out it was already threaded, Armalite said it was pressed on.

BTW sniperx, the hardwood blocks worked perfect to get the barrel nut loose, my AR-10 project is now complete, Thanks.




I am glad you got your 10 fixed up.


FYI The brakes that are pinned and welded have threaded barrels.
The brakes that have two pins in the bottom are pressed on.
The ones that are pressed on you are much better off machining them of in a lathe
or doing the split job. They are about .005 tight plus are on a knurled surface. Once removed
the barrel can be turned down and threaded. You can not just run a die nut over it as the diameter is over sized.




That's good to know, my buddy wants me to do his next. I'll check it out.
Belial  [Team Member]
8/4/2005 9:49:22 PM
Mine was at 6:00 and was at an angle toward 3:00. I cut the end off with a cutoff wheel then cut about 90% of the way to the threads the a grinder. Finished up with a small cutting wheel on the dremel tool. I went very slowly and when I got close to the threadsthe last bit of metal started flaking on top and bottom. I cut a groove in the muzzle end and used a chisel to split the remainder off. Took about 15 minutes and didn't do any manage at all...
lawndartF16  [Member]
8/10/2005 10:42:32 PM
I am a lazy prima-donna s.o.b. (so says my mom). I dropped mine off with my gunsmith this am with a pile of other, more interesting work. Before I got back to the highway he called me on my mobile phone to come back and get the AR-10 barrel because it was done.

The great news is that the AR-10, my short barreled .308 bolt, and my 300 Win Mag heavy rifle are all threaded identically so I can use one suppressor for all of them. Ka-CHING!

lawndart