I just ordered a 14.5" DD barrel for my DD M4V4 due to reading quite heavily on the benefits of the 14.5's over 16's with a carbine gas system. I also just ordered an AAC 51T Blackout muzzle brake to soon accompany my AAC M4-2000 suppressor that I'm still waiting on the paperwork for.

Now the question is, how exactly do I go about mounting my AAC brake on my 14.5" barrel to make it legal without having to get a tax stamp for it? Both parts should arrive within a week or two, and I would like to get them up and running ASAP when they do.

On another note, any feedback on how much I may regret having a carbine gas system instead of a mid-length gas system on my 14.5" AR? Unfortunately, it wasn't until after I purchased my M4V4 that I realized I could have went with the M4V5 for the same price with a mid-length system. I then started reading a lot of praise regarding mid-lengths in comparison to carbines, but my local gun shop has a no return/exchange policy on firearms. Hopefully I won't regret it too much down the road...

Any thoughts or feedback is much appreciated.

Send upper to ADCO and have them pin/weld the Comp on for you.. it will put you over 16" I think..

Unless you have 2 stamps going.. 1 for the can and one for the SBR stamp??

Do you have a lower with a RRA  (aka cheap) pistol tube on it?? stick the barrel/upper on it.. and done.. till you get stamped or pin/welded.. based on Q #1 and Q #2..

*the MIL runs Carbine 14.5" if this helps ease your buyers remorse..

Not sure the length of youe flash suppressor and am to lazy to look
It up..... have it pinned/welded and make sure it 16 " oal
And you are good to go

Send it to ADCO and they will pin/weld a fglash hider to make it 16.1" OAL.

This would be your best option. They can also check to make sure the threading is concentric to the bore. This is something you will need to have done to run a suppressor. You don't want to be getting baffle strikes.

I appreciate the input thus far, and there has been a recent change to my future configuration...I got a refund on my AAC M4-2000 suppressor and AAC 51T brake, and have decided to go with a Battlecomp 1.5 brake instead.

After a ton of research, I have decided that I would rather go the suppressor route on the 10" Noveske 300 Blackout that's gonna be my next rifle purchase...and I can now also put the extra cash coming back towards the Trijicon ACOG TA11 or TA33 that I'm currently eyeing for my DD M4V4.

Quick question. For those of you recommending shipping my barrel and brake off to ADCO for welding, would that still be the best route to go with my 14.5" DD barrel and Battlecomp 1.5 brake? Particularly curious since I would now have no intention nor option of adding a suppressor down the road. I clearly need the two permanently attached, and would prefer to do so in the best option available.

I would still say they are the best game around for what you want. Just be advised if you ever decide you want something else, it will have to pretty much be cut off and be useless for resale.

Send it to Adco you won't be sorry, they do nice work and return quickly.

Thanks. Looks like I'll be shipping off to ADCO once my 14.5" barrel and Battlecomp brake arrive.

Is this something that should be done regardless of if I intend to run a suppressor or not? I have no intentions of adding a can to this particular AR down the road.

I just submitted my order with ADCO, and mentioned the threading in my order comments, and inquired if it was something that should be done to achieve best results out of the barrel.

I don't know how long it will take to hear back from them, so I'm just curious. I would obviously like this process to be done in the best way possible.

Adco is fast!  They just pinned my BattleComp.  Sent it to them from SC on Monday and got it back on Friday

Its not important unless you want to run a can. You said AAC and I assumed supressor mount.

If it's truly a 1.5" brake, you're out of luck, because the threads overlap the barrel by about .55".  You need a 2.1" OAL threaded muzzle device to permanently attach and bring the barrel to >16" OAL to avoid it being an SBR/pistol barrel.

There are special long muzzle devices sold for this purpose.

What can do you have for the 300?    Unless it's a thread on can you could always have the mount for it attached anyway.

 

If you have a drill press you could do the pin yourself. You dont have to have it soldered and pinned. Just one of the two. But if you go the solder route make sure it is the proper heat resistant solder. Brownells sells some good stuff if you just want to solder. To pin it, put the break on- measure the set up and make sure it is at least 16". Then put it in the press and set the depth of the bit and drip it. Tap the pin in and place a small amount of solder over the pin and your gold.

You could just solder the break on and be done with it.

Most people don't have the tools to do sliver solder or welding, let alone the skill.

The BattleComp 1.5 has been specifically designed to be perm attached to 14.5" barrels to achieve an OAL of 16.1". It's been extended in size from the 1.0 and 2.0 versions.

I'll be picking up an AAC 762-SDN-6 can for my future Noveske 300 Blackout.

Not only do I not have the tools, but the only work I have done thus far on an AR-15 is stripping one down to clean, and installing a Geissele trigger...I think I'll leave this one for the pro's - unless it was something fairly easy to do.

You say it's not important unless I want to run a can, but could it hurt? I'm just curious why the threading would come into play with a can, but not without one. I would think the bullet would travel better regardless. Just curious as I need to let ADCO know exactly what I need done.

I'm also curious if I actually need them to weld on my muzzle device, or solely pin it. From what I have been reading recently, it appears only certain states require it to be pinned and welded, while others would be fine with simply a pinned device.

If the threads on the barrel are not concentric, the supressor wont be centered on the barrel when threaded on, and the bullet could strike the baffles of the suppressor.  Wont matter with a standard muzzle device, there is a lot more clearance than a supressor.

For those of you who have used ADCO for shop work before, I'm a little confused as to how the entire process works once I have submitted my online order...they don't really make it quite clear.

My order is showing as "being processed" when I bring it up on their site, and the only communication I have received from ADCO was the initial confirmation of my online order via email.

I'm just curious if I'm already supposed to ship off my barrel and BattleComp, or if they eventually review the order and get back to you with more detailed instructions.

NFA is Federal. State rules cannot supersede Federal law.