Going to build a Short Barrel Rifle (AR).

[Infidel4life11]

I've been thinking for while about a SBR AR-15. On my way to work today I finally decided I'm going to do it. My idea is the total length (comp and barrel) being under 16". It will be a mid-length gas system, Cold Hammer forged barrel 1:7.

Magpul UBR stock
Magpul MAID grip
H buffer or Spikes
Magpul BUIS
Aimpoint micro t1
Magpul MOE foregrip or AFG2
Geissele trigger/timney trigger maybe. I like a mil-spec but the trigger will be tuned
Flash hider- Battle Comp or Noveske Krink KX3 with Pig
Receivers- I'm thinking a Spikes tactical set or BCM- I need some good opinions
Handsguards-LaRue Tactical 11.0-12.0", Daniel Defense Modular Float Rail Assembly 12.0- I need opinions on this too, I want free float I don't care if it's a quad rail or not I'm not going to hang a bunch of crap off the front of this thing.
Everything will be high end "Top Tier" if you will. I'm open to ideas, the barrel will be between 12"-14"

 

[Birddog1911]

You've got a lot planned there.

First; I've not had a midlength in a while, but if my coffee lacking brain is correct, you could not use a midlength gas system on an SBR.

Think about how you're going to shoot it. I shoot mine with the stock collapsed, so a standard grip angle wasn't that comfortable. I was much happier when I put BCM's new grip on; the angle is perfect for shooting with the stock short.

BCM is a great company, and never done me wrong. Palmetto State Armory is also a great company to work with.

My Mk18 Mod 0 clone:

 

[sniperlongshot]

just make sure that you get the form one back before you get all your toys in the box, just having all the parts to build it constitutes intent to assemble and that can get you into trouble, ............what i did was buy a virgin receiver that hasn't been assembled, no tirgger etc........have the shop sell you the receiver as a pistol receiver on your receipt (and keep that with the gun in your lockable hard case), build a pistol first, (make sure you know if your going to use a 4 or 6 position buffer) for overall length on the form one, ............ once you get back the form one, then install the buffer and stock......."you can beat the rap, but not always the ride", don't take the ride if you don't have to, many will agree what i just told you to do is not nec., but it's safer, alot of the NFA agents are great people, but many have no sence of humer when it comes to mistake that amount to violations.

 

[Birddog1911]

You can go the pistol route, or just buy the rifle lower, send off your form, and wait for it to return before buying the rest of the parts. But yes, you do not want to have a SBR upper fully ready to go, with a rifle lower anywhere near it until you've got your stamp in hand.

 

[TonyAngel]

Are you going to go with a suppressor? If not and you go for a 16" overall length, make sure that the trouble and expense is worth it to you. In any case, going with a 14.5" barrel doesn't necessisarilly mean you you have to "sbr" the rifle. You could just pin the muzzle device. It's cheaper and faster.

If I was going to sbr a rifle, it would be shorter than 16" overall.

 

[CCH71]

You can have a midlength gas system if you go with a 14.5" barrel. My daughter's carbine is a Daniel Defense middy 14.5" barrel. With the 14.5", the mid system and the additional mass of an H2 buffer and full auto BCG it shoots like a big pellet gun. It's a very pleasant combo.
Pic was a while back during construction, but you get the idea.

 

[Infidel4life11]

Are you going to go with a suppressor? If not and you go for a 16" overall length, make sure that the trouble and expense is worth it to you. In any case, going with a 14.5" barrel doesn't necessisarilly mean you you have to "sbr" the rifle. You could just pin the muzzle device. It's cheaper and faster.

If I was going to sbr a rifle, it would be shorter than 16" overall.

Thank all you guys for the info. Tony I will have a 14.5" with a pinned comp on another rifle already in the process. A suppressor from AAC is in the works also. This thread is because I am also building a rifle with a barrel under 16" total I haven't decided on length yet but probably close to 14" w/comp attached idk just yet. I've shot a few 10.5 barreled rifles with standard A2 birdcage compensators and didn't enjoy them at all.

 

[Infidel4life11]

You can have a midlength gas system if you go with a 14.5" barrel. My daughter's carbine is a Daniel Defense middy 14.5" barrel. With the 14.5", the mid system and the additional mass of an H2 buffer and full auto BCG it shoots like a big pellet gun. It's a very pleasant combo.
Pic was a while back during construction, but you get the idea.

That right there fellas is my general idea. Maybe a little shorter but not much.

 

[Birddog1911]

So it sounds like you're not actually going to build a SBR?

 

[Infidel4life11]

No I am the total barrel length with the flash suppressor will be under 16". The sound suppressor I'm still on the fence about. And so that I don't confuse you guys here is some pics of my intent. I think 12.5" barrel is where I want to be.

 

[TonyAngel]

Infidel, maybe you should give Bravo Company a call and ask them. If I recall right, they actually had their preferences for length of barrels on SBRs based on their intended uses, ie., suppressor or not.

Based on my recollection of the thread that I read, they did some tests and came to some conclusions. Unfortunately, I can't remember what those conclusions were or why.

Please, let me know what you decide to do and why. The suppressed SBR bug has bitten me too. I got to shoot a 12.5" barrel ( I believe it was) with a rimfire conversion in it on a full auto lower a couple of months ago. I couldn't sleep that night just thinking about it.

 

[JustinJ]

I've read about issues running a mid length on a 14.5" barrel although it was primarily with russian ammo thought to be under powered. While i don't run that stuff it would concern me that heavy fouling may provide enough resistance to make the rifle unreliable. The carbine length is tried and true on a 14.5 so i'd stick with that.

 

[CCH71]

Mid is arguably a better choice on a future or current suppressor candidate. It will have less of an over gassing predisposition when the additional back pressure is introduced from the can.

Keep in mind that a lot of the engineering choices that went into an issue M4 were influenced by the need for automatic fire. I have no complaints or concerns with a mid length and 14.5" combo on a semi-auto range plinker. There is still quite a bit of dwell past the gas port and I've had no cycling issue, even with reloads that are underpowered by NATO 5.56 standards (23.5gr H335 under a 55gr).

 

[Infidel4life11]

Tony, BCM will be who I get the barrel from and most of the parts for this build. I want to built this on my own but my 1SG just called me stupid and told me I should just call BCM buy one of their rifles lol. I'll keep you posted

 

[rjrivero]

My SBR preference is an 11.5" with an Ops Inc M4S Suppressor. Not hearing safe, but works a LOT better than the flaming pig does. Here it is pictured with it's full 16" brother wearing an Ops 16th Model.

 

[BLAKEinTX]

I just built a 12.5" upper for a customer it is not a midlength gas system though i have never seen a bbl with midlength gas under 14.5"

I have on my POST86 M16 a DD 14.5" with midlength and it runs everything including the russian crap the only problem ive had with it was a buffer problem and making it trip the auto sear and letting the hammer ride home with the bolt

Anything in the NFA bbl length realm will be loud as tits its physics and I would recommend getting a can for this gun or a couple of guns they are just common sense to have

I can post pics of that upper if you would like just let me know

 

[Infidel4life11]

I just built a 12.5" upper for a customer it is not a midlength gas system though i have never seen a bbl with midlength gas under 14.5"

I have on my POST86 M16 a DD 14.5" with midlength and it runs everything including the russian crap the only problem ive had with it was a buffer problem and making it trip the auto sear and letting the hammer ride home with the bolt

Anything in the NFA bbl length realm will be loud as tits its physics and I would recommend getting a can for this gun or a couple of guns they are just common sense to have

I can post pics of that upper if you would like just let me know

Thank you please do!

 

[BLAKEinTX]

Larue upper, 10.0 rail, and BCG
DD 12.5" bbl
YHM lopro gas block and tube
PRi Gasbuster
SF muzzlebrake

 

[Infidel4life11]

Well looks like I'll be going with a 12.5" barrel and carbine length gas system. Larue rail as of now receivers from spike's are on the way. I picked up a bunch of stuff from the gunshow this past weekend and thinking about an ALG trigger. To keep you up to date I have a bushmaster MOE that continues to get new parts round count around 1800, a well used M&P sport that continues to impress me, some sort of RRA flat top M4 thingy with a pretty nice stage two trigger (paid $300)lol it shoots pretty good, building a PSA/Spikes for a friend, looking for a Sig M400 or 516 to buy, buying parts for this SBR build and my father well be coming into town and he wants to buy me a all in one present for bday, christmas etc etc which will hopefully be a BCM EAG tactical. I have to make a trip to texas and pay for some schooling this fall. Needless to say the funds are going to slow down and the paperwork for this SBR may take 6months or longer so I will do my best to keep y'all informed on this build but I may have to start new threads for it once I get all parts together.