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View Full Version : AAC Brakeout pin and weld *pictures at the end*


surfish95747
11-15-13, 23:35
Alright guys, just wanted to put up my pin and weld experience. I have a 14.5" Daniel Defense barrel that needed a muzzle device pinned and welded. I decided to go with the AAC Brakeout so that in the future I can put on a M4-2000 suppressor.

I started out by choosing a 3/32 x 3/4" steel dowel pin. After securing the Brakeout in a set of nylon vise jaws, I used a drill press at my cousins machine shop to drill a hole into the Brakeout. The drill press had a (pardon my lack of machine shop and drill press terminology) swivel table and a movable vise. It made it very easy to adjust and get just right.

I wanted to drill my hole in between the ratchet teeth and the suppressor threads (where the white dot is in the picture), but we were worried that would be too close to the end of the barrel, or not on the barrel at all. So, we centered the Brakeout in the vise jaws and using a center punch marked our spot right in the middle of the ratchet teeth. This made me nervous but it worked. After drilling the hole through the Brakeout I ran into my first problem. I had gummed up the threads on the inside and now could not thread the Brakeout unto the barrel. We tried to find a 1/2 x 28 tap but could not as that was too fine of a thread to be found at my cousins shop. So, I used a different tap with similar thread to "scrape" out the inside and get rid of a few burs. This worked and I was able to, with a little force, thread the Brakeout onto the barrel.

With that I placed the upper receiver in my upper receiver block and tighten it down in the vise. With the Brakeout finally timed on the barrel, which took me about 30 minutes of mixing and matching the bleeding shims, I torqued it down to just over 30 foot pounds of torque. Just over 30 foot pounds because it was just about perfect at 30, but not quite, so it may be torqued down to 31 or 32 foot pounds. Not too bad.

With that I took my drill bit and corded (can't stand underpowered cordless) drill and prepared to dimple the barrel. This was the most nerve wracking part for me because I didn't want to jack up my $300 barrel, which at this point in life, I would not be able to replace. Anyways, I taped off a measurement of 1/8" on the drill bit and started to drill. Using a little cutting oil seemed to help the bit cut faster. I slowly drilled down 1/8 of an inch into the barrel and had a perfect dimple. I cleaned out the hole and prepped it for the dowel pin. Adam, at the shop helped me cut the dowel put so it sat just under the surface of the teeth. With that we tapped it in and Adam, using a MIG welder, made a very nice and clean weld over the pin and hole, completely welding it shut, permanently attaching the Brakeout to the barrel.

After that, I borrowed my cousins rock files, a flat one and diamond shaped one to clean up the weld mound left over. I filed the weld mound flat and flush with the other Brakeout teeth. Them I took the diamond shaped file and started reshaping the ratchet teeth to match the others. I still have a little more filing to clean up the teeth, but they are nearly perfect. The pictures don't do it justice but they turned out better than I could have hoped. Thanks for looking and reading. It was fun to do it myself, quite the little challenge and nerve wracking moment.

http://i848.photobucket.com/albums/ab43/surfish/IMAG0934_zps2c368cd5.jpg

http://i848.photobucket.com/albums/ab43/surfish/IMAG0933_zps5df774f7.jpg

http://i848.photobucket.com/albums/ab43/surfish/IMAG0929_zps7154875f.jpg

http://i848.photobucket.com/albums/ab43/surfish/IMAG0928_zps612e11d7.jpg

http://i848.photobucket.com/albums/ab43/surfish/IMAG0928_zps78488935.jpg
surfish95747
11-18-13, 22:30
Just a quick update. Today I took my gun to Get Some Guns and Ammo in Orem UT, and asked if the could test an AAC M4-2000 on my Brakeout to see if the teeth would still ratchet properly. Everything worked. The suppressor twisted on beautifully. I am happy. Great weld job, right through the teeth. Love it.
surfish95747
11-19-13, 02:11
*Range update. Just took it out to the range and only put 60 rounds of Federal XM193 55 grain I think it was through it. Ran flawlessly. That mid-length gas system is so soft. I barely felt any recoil, and the AAC Brakeout, made it a flat shooter. No movement at all. Love it. Now I need a suppressor. Oh boy, I'm hooked.

If anyone is interested here is a video of my first shots. I apologize for the lighting, my B5 Systems stock took a little longer than expected to get off the UPS truck today. Anyways, I am a bit of a goofball, so bear with me.

http://youtu.be/_mgvT5lW4n8
Suwannee Tim
11-19-13, 19:13
Pretty good job for a machine shop noob I say.
Shorts
11-20-13, 08:09
Yep, good work getting the job done. I like your attention to detail to get the teeth reformed.
MarkG
11-20-13, 08:29
Curious as to why you didn't just run the pin through the collar at the back of the device between wrench flats. Does it overlap the shoulder of the barrel?
Hkbeltfed
11-20-13, 09:49
Curious as to why you didn't just run the pin through the collar at the back of the device between wrench flats.

Noveske pins on that collar, but through the flat. Mine looked perfect.
mtdawg169
11-21-13, 15:30
Noveske pins on that collar, but through the flat. Mine looked perfect.

There's a reason they don't pin through the teeth.
Shorts
11-21-13, 18:15
There's a reason they don't pin through the teeth.

I'd be taking a few guesses but mind sharing why?
scottryan
11-21-13, 19:41
Why did you not do an SBR if you live in UT?
Steve S.
11-21-13, 22:54
I'd be taking a few guesses but mind sharing why?

Wouldn't that be near the barrel crown?

Also messing with the teeth could have an effect on the suppressor possibly?

Does look good though.
mtdawg169
11-22-13, 13:30
I'd be taking a few guesses but mind sharing why?

For starters, the finish has been removed and with it the hardness of the original mount & teeth. Manufacturers also don't want to have to reshape the teeth or deal with potential lockup issues with the suppressor. The reformed teeth could wear faster and lose their ability to properly lock up with the ratchet. My educated guess is that if the suppressor were damaged later due to coming loose on the mount and getting a baffle strike, it probably would not be covered under warranty. Bottom line, they pin it forward of the ratchet teeth because it creates potential mount issues and possible liability.
markm
11-22-13, 13:35
Assuming the can latch engages somewhere else on the mount, I don't see this being a big problem.

It's good practice to hold the latch open when installing the can anyway to keep the engagement teeth from rounding off.
mtdawg169
11-22-13, 16:10
Assuming the can latch engages somewhere else on the mount, I don't see this being a big problem.

It's good practice to hold the latch open when installing the can anyway to keep the engagement teeth from rounding off.

Good point, but if it was pinned forward of the teeth, you don't have to worry about it at all.

By the way, good to see you again Mark!
Hkbeltfed
11-23-13, 10:04
Good point, but if it was pinned forward of the teeth, you don't have to worry about it at all.

Why forward of the teeth? Why not behind them?
mtdawg169
11-23-13, 11:28
Why forward of the teeth? Why not behind them?

On that particular mount, the collar behind the teeth recesses over the barrel shoulder. The few factory pin jobs I've seen were drilled so that the pin went into the threads, but it would probably work fine either way. Personally, I can't stand pinned muzzle devices. I'd rather have a 16" or an SBR lower. I'm finally getting around to building a 14.5 midlength, but it will be run on my SBR, so I don't have to fool around with pin & weld.
Shorts
11-23-13, 11:42
For starters, the finish has been removed and with it the hardness of the original mount & teeth. Manufacturers also don't want to have to reshape the teeth or deal with potential lockup issues with the suppressor. The reformed teeth could wear faster and lose their ability to properly lock up with the ratchet. My educated guess is that if the suppressor were damaged later due to coming loose on the mount and getting a baffle strike, it probably would not be covered under warranty. Bottom line, they pin it forward of the ratchet teeth because it creates potential mount issues and possible liability.

I see. Appreciate the elaboration.
surfish95747
03-16-14, 02:20
Why did you not do an SBR if you live in UT?

Thanks guys. It was fun either way. I'm a long way off from getting a suppressor anyways. Also I didn't have $200 to SBR my lower, but I did have everything to pin the device myself. I would love to have an SBR but something more along the lines of an 11.5" incher. Suppressor ratchets on just fine however.