First NFA AR15 Build

[fyroc]

After much thought on what to build with these 5 stripped lowers I bought, I've decided to do a NFA build. I've done many builds before, but never anything requiring a stamp. I'm not going to get the NFA items right away, but it will eventually be surpressed and a SBR.

So for now, I'm going to build a pistol lower and then once I'm ready to build the SBR I'll use another lower specifically for the SBR. This way if I need to convert it back to a pistol for any really, it would be just a simple lower switch.

Parts list so far:
Anderson Lower
PSA 10.5" CHF 5.56 NATO A2 Profile
PSA FDE MOE LPK
Carbine buffer/spring
Shockwave Blade with tube FDE
Vltor FDE handgaurd
DD fixed BUI
Leatherwood Tac-dot
Flash hider for suppressor undetermined

 

[Strider12]

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[fyroc]

Also, you you guys have any suppressor/Flash hider suggestions?

 

[T-Roy]

Also, you you guys have any suppressor/Flash hider suggestions?

Personally I would stick with a standard a2. You definitely don't want a brake on a short barrel, & I just don't see wasting money on some kind of fancy flash hider. I do have a Noveske flaming pig on my 7.5 barrel and it does work pretty well, though it's bulky and heavy

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[Cudruln]

After playing with a suppressor this past weekend I would highly recommend looking into it. @DoglegArms would be the guy to talk to about suppressors

 

[Cudruln]

As far as the other parts for the build seems like everything is there.

Just don't forget the bcg. Not sure if you planned on it coming with the upper.

 

[Kaotiktribe]

Fixed BUI?

Will your optic co-witness?

 

[Mac11FA]

As far as the other parts for the build seems like everything is there.

Just don't forget the bcg. Not sure if you planned on it coming with the upper.

Go with the FA BCG. The extra weight will help improve lock time.

 

[DoglegArms]

Did someone say suppressor?

10.5" or 11" barrel + 6"-7" can = might as well permanently attach a can and pay a single tax stamp.

 

[boss_hawg]

I assume you're talking about 5.56/.223 caliber?

 

[fyroc]

Did someone say suppressor?

10.5" or 11" barrel + 6"-7" can = might as well permanently attach a can and pay a single tax stamp.

Nah. The reason for this build is so I can have something that will easily fit into a duffel bag. This will be my traveling rifle/pistol. Which is why I'm doing 2 different lowers. The suppressor will be more for fun.

I assume you're talking about 5.56/.223 caliber?

Correct

Go with the FA BCG. The extra weight will help improve lock time.

Yep! I was planning on doing so. I didn't mention it above because my go to BCG is a FA BCG.

Fixed BUI?

Will your optic co-witness?

It might. If not, it will be a little off. The Vitor CASV will raise the red dot but keep the BUIS at it's normal level.
It's going to be loosely based on the Navy EOD's MK18,

 

[boss_hawg]

not to get into debates of ballistics but I went with a 12" chf barrel vs. a 10.3 or 10.5. I like the extra couple hundred fps or so, and the price was right. I realize it isn't correct for a clone build but I wasn't going with a LMT or DD RIS anyway.

 

[boss_hawg]

here's a pic (or two) of mine. I'm waiting on a skinny car hand guard that I'll rattle can like the rest.

 

[becausefu]

not to get into debates of ballistics but I went with a 12" chf barrel vs. a 10.3 or 10.5. I like the extra couple hundred fps or so, and the price was right. I realize it isn't correct for a clone build but I wasn't going with a LMT or DD RIS anyway.

An inch and a half of barrel isn't going to produce an extra 200 fps .....you MIGHT see 50 fps difference

 

[boss_hawg]

The article I read demonstrated a roughly 300 fps loss on average when moving down from an 11.5" to a 10.3" barrel. The loss of roughly 50 fps / inch occurs when moving between 20" and 14". The graphical plot of fps vs. barrel length is non-linear with a steeper slope at lower barrel lengths due to the nature of powder burn rates in most 5.56/.223 ammo.

 

[boss_hawg]

I can PM you the article but would rather not post a link to another forum taking members away from this site.

 

[T-Roy]

The article I read demonstrated a roughly 300 fps loss on average when moving down from an 11.5" to a 10.3" barrel. The loss of roughly 50 fps / inch occurs when moving between 20" and 14". The graphical plot of fps vs. barrel length is non-linear with a steeper slope at lower barrel lengths due to the nature of powder burn rates in most 5.56/.223 ammo.

I've read similar articles and will back you up. From what a remember 10.5 is the MINIMUM barrel that will produce effective velocities in 5.56

The maximum velocity for the M855 projectile occurred in a 20-inch barrel. This is anticipated since the cartridge was designed specifically for this barrel length. Velocity drops rapidly as the barrel length decreases, especially below 10 inches where the velocity drops below 2,500 fps. M855 bullets traveling below 2,500 fps when impacting a target will not produce a lethal wound channel.

http://www.sadefensejournal.com/wp/?p=1093

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[DoglegArms]

The article I read demonstrated a roughly 300 fps loss on average when moving down from an 11.5" to a 10.3" barrel. The loss of roughly 50 fps / inch occurs when moving between 20" and 14". The graphical plot of fps vs. barrel length is non-linear with a steeper slope at lower barrel lengths due to the nature of powder burn rates in most 5.56/.223 ammo.

There's something wrong with 300 FPS loss between 11" to 10". What powder was being used?

Seems like on avg it's a loss of 50-100 FPS from 11" to 10" depending on what powder.

http://www.accuratereloading.com/223sb.html

 

[boss_hawg]

Here is the article I read showing the averages of five shot groups from 10.3", 11.5", and 14.5" barrels.

https://www.ar15.com/archive/topic.html?b=3&f=118&t=509733

 

[boss_hawg]

Also, I was looking at a 12" vs. a 10.5" barrel. Again, I'm not saying that 10.3/.5 won't get the job done but velocity is important with 5.56.