AR CQB build

[ZLBubba]

I want to upgrade my RRA carbine a bit. I'm planning on using a 12.5" Compass Lake barrel, a Noveske KX3 flash suppressor, and a DD Omega 12" rail. From what I've read, the 12.5" barrel with a pinned KX3 should get me to 16.1" to make it NFA legal.

I wanted the longest rail system I could get, but I'm worried that the rail may be too long and that I'll need to find an 11" rail system to make this setup work. Does anyone have a build like this? Will I be NFA legal? Will the DD 12" rail work, or should I go with an 11" to be safe? Also, what gas block would you suggest for the Compass Lake barrel? Thanks for the help.

On a final note, can I un-pin the KX3 if I decide to register the lower as an SBR?

 

[Calibur6918]

Re: AR CQB build

after you engrave the lower with the Serial and name you can unpin it. Piece of advice, don't get an extra long FF rail, it will be cumbersome and you wont want to carry it. I had a 16"barreled AR and installed a 12" rail. i regretted it shortly after and wish i had the 7".

 

[bm11]

Re: AR CQB build

Here is my advice-

I know you want the cool look of a short barrel, but if your overall length is going to be 16 anyhow, how about you go with a 14.5 inch barrel and a 1.6 inch flash hider? You'll be ahead of the curve by a few hundred FPS, and can get away with a longer (carbine length) gas tube with better feed reliability.

I say this because you are going to end up at the same OAL anyhow, so you aren't sacrificing anything. It would be one thing if it were a registered SBR with a legit 12.5 barrel, but this is a horse of another color.

 

[TXTransplant]

Re: AR CQB build

+100 on what bm11 said.

Having a "fake" SBR is a bit retarded from every practical standpoint, though of course coolness factor is personal taste.

It is way sweet to have a barrel that is 16.1 OAL, they definitely handle better, but the best way to approach it is more functioning barrel and less non-velocity increasing BS (flash hider etc).

Speaking generally, barrels under 14.5" have more problems, are harder to tune to run right under all conditions, and you're also at a length where you're talking major velocity loss per inch of barrel loss.

IE a 12.5 inch barrel set-up as you propose above will shoot slower bullets, run less reliably, have more muzzle flash, AND all that for being the exact same overall length as a 14.5 inch barrel with a pinned Vortex or similarly long flash suppressor.

If you're going SBR, just fill out the paperwork, do it for real and have a shorter gun. Otherwise, you're losing a lot and gaining nothing. You will be downgrading your RRA carbine, not upgrading it.

 

[TXTransplant]

Re: AR CQB build

But yeah it's usually easy to unpin--just carefull drill out the pin in the flash suppressor, watching your depth of cut the whole time. It's only welded at the surface.

 

[chawk]

Re: AR CQB build

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TXtransplant</div><div class="ubbcode-body">+100 on what bm11 said.

Having a "fake" SBR is a bit retarded from every practical standpoint, though of course coolness factor is personal taste.

It is way sweet to have a barrel that is 16.1 OAL, they definitely handle better, but the best way to approach it is more functioning barrel and less non-velocity increasing BS (flash hider etc).

Speaking generally, barrels under 14.5" have more problems, are harder to tune to run right under all conditions, and you're also at a length where you're talking major velocity loss per inch of barrel loss.

IE a 12.5 inch barrel set-up as you propose above will shoot slower bullets, run less reliably, have more muzzle flash, AND all that for being the exact same overall length as a 14.5 inch barrel with a pinned Vortex or similarly long flash suppressor.

If you're going SBR, just fill out the paperwork, do it for real and have a shorter gun. Otherwise, you're losing a lot and gaining nothing. You will be downgrading your RRA carbine, not upgrading it.

</div></div>

I agree with this completely.

 

[BasraBoy]

Re: AR CQB build

On the fore-end, have you looked at the DD AR Lite mid length? It is extended to 10" (not standard 9.0"):

http://www.danieldefense.com/?page=shop/detail&product_id=159

I've got one for my 18" barrel as I wanted a more "wieldy" rifle but thoght it would be just plain wierd to go with a 6.0 Carbine length on the barrel.

 

[Bruiser_Joe]

Re: AR CQB build

you need a 13.7 to have a kx3 and be 16" just a FYI