Posted on March 27th, 2013 by ar15news
I’m really excited to finally fully reveal to you guys the official AR15NEWS AR Pistol Build. Here in Michigan we are not allowed to own SBR’s so this is the next best thing unless I want to move. In this write-up I will go through all of the individual parts that I selected for this build, explain the particulars of building an AR Pistol and then give you guys a look at the finished product. I’ve already had a chance to take this gun out to the range but the range report will be a separate write-up.
I want to start first with the lower receiver of the pistol build as this is the most important part of the whole process. Please keep in mind that I am in no way “legal council” and am only explaining what I did for my AR Pistol build. If you plan on doing the same I urge you to do your own research.
THE LOWER RECEIVER
A common misconception regarding building an AR Pistol is that you have to buy a “PISTOL” marked lower receiver. From all of the research I’ve done as well as consulting two very knowledgeable friends on the matter it is very apparent that you do not need a “PISTOL” marked lower receiver. All you need is a virgin lower that has not been assembled yet. AR15 Lowers are typically transferred by your FFL as “other” and then marked as a receiver which gives you the option to build it as a Pistol or a Rifle. You need to document the process as you build this receiver into a pistol being clear that it was never configured as an AR-15 Rifle prior to becoming an AR15 Pistol. To configure your AR15 lower into a pistol you need to have a buffer tube that does not accept a stock of any kind. I personally chose an Umbrella Corporation Weapons Research Group forged lower receiver and a Phase 5 Tactical PBT (Pistol Buffer Tube) which you will see in the pictures below. I will also be leaving the serial number visible in these pictures as part of the documentation process. I’ve put a bunch of links at the bottom including the ATF document that explains this.
The pictures above show exactly how this AR15 lower was assembled its first time as an AR Pistol having never been assembled as a rifle. The UCWRG Lower is absolutely awesome and was a CHRISTmas give from them which was a very nice surprise. I went to purchase one and they said it was on the house. Good guys over there. I also added an UCWRG Rifle Grip. The more vertical angle definitely makes it much more comfortable shooting this bad boy. As you can see there is no way to attach a stock of any kind to the Phase 5 Tactical PBT (Pistol Buffer Tube) but it does come with the awesome foam pad installed to add some comfort. A few of the additional components I chose for this build were the BAD-CASS-SA safety selector from Battle Arms Development, a Mega Arms Tactical Trigger and the EBAL (Enhanced Battery Assist Lever) from Tactical Link.
THE UPPER RECEIVER GROUP
My next order of business was figuring out which barrel/caliber to use. The heart of any rifle is the barrel so I had to get an awesome barrel for this build. Many of you know that I love Rainier Arms and I love 300AAC Blackout so I honestly had my mind made up that I was going to buy one of their 300AAC Blackout barrels and that is exactly what I did. I got on the email notification list for the 10.5″ 300AAC Blackout UltraMatch barrel with a pistol length gas system. As soon as it came in-stock I was all over it like white on rice and wasted no time in purchasing it. The 300AAC Blackout works great with pistol length gas systems but I really wanted to try something different so I decided to purchase a Pigtail Gas Tube and Low Profile Gas Block from my buddies over at Phase 5 Tactical. By wrapping the gas tube around the barrel a few times it helps pistol length gas systems cycle better and is closer to a rifle length gas system. My only concern was that due to the lower pressures of the 300Blk round it may cause it to not have enough gas thus causing cycling issues. (Thankfully that was not the case!) For the muzzle device I decided to go with a BattleComp BABC. I love me some BattleComp so this was an easy choice.
Now that I had the barrel and hardware all sorted out I needed an Upper Receiver, BCG, Charging Handle and some sort of Handguard/Rail. I already had the best charging handle $$ can buy…a Rainier Arms Raptor Ambi CH so I was all set there. I also already had in my possession a Rainier Arms BCG. I chose a 10″ Seekins Precision BAR rail for its size. It has a slightly larger circumfrence which I preferred for this build. I have fairly large hands so it gives me some thing of substance to wrap them around. Not to mention its sweet looking and is a very high quality rail.
I knew going into this the hardest part to find was going to be the Upper Receiver. Every manufacturer out there is pumping out lowers and the uppers are on the back burner. I have a pretty active Instagram account and was tagged by a guy named Dustin from CIV Tactical. I took a look at the awesome AR15 uppers he was building and the rest is history. We hit it off pretty quickly and got to talking about my 300Blk Pistol build. He was gracious enough to give me one of his uppers that he had done some custom work on called Blueprinting and Lapping. He basically uses a lathe to remove the slightest amount of anodizing and material from the front of the receiver face to make sure that the barrel, bcg and upper are all in perfect alignment This a common process done on custom precision rifles but has show to dramatically increase the accuracy of a an AR15. I’m not doing my range report just yet but this thing blew my socks off.
The last step was to assemble the upper receiver group and add a few accessories such as a set of Magpul MBUS, Magpul AFG and an INFORCE WML. I went with the WML for two main reasons. First, the WML is a great light and I really like it. The second is that due to a shorter rail I wanted something I could position where my thumb would naturally be when wrapping my hand around the rail. By mounting the WML on the top of my rail at the very front, it allows me to wrap my hand around the AFG and Rail while placing my thumb right in between the WML and MBUS. The activation switch for the WML is right at my thumb so I can activate the light without changing my grip at all. I love this setup! I also used a PMAG from A Breon Custom which has the words “300 Blackout” infused on it. For the optic I wasn’t sure if I wanted to use my Aimpoint PRO or an Aimpoint T-1 but I ended up going with the T-1 because of the weight and size difference.
THE FINAL PRODUCT
Now that you all know every last detail to my AR Pistol its only right to let you see it in all of its glory. Below are a few pictures of the complete AR15NEWS AR Pistol Build. As I mentioned before I have already taken the AR Pistol to the range and will do a full range report very soon. Needless to say this build far exceeded my expectations and is my absolute favorite gun I’ve built so far. Please check out the links at the bottom for more information and to purchase the parts I used in my build.
BUILD COMPONENT LINKS
A Breon Custom PMAG
Aimpoint T-1
Battle Arms Development BAD-CASS-SA safety selector
BattleComp BABC
CIV Tactical Upper Receiver
INFORCE WML: Use code “AR15NEWS” to save 5%
Mega Arms Tactical Trigger
Phase 5 Tactical PBT, Pigtail and Gas Block
Rainier Arms Barrel and Raptor CH
Seekins Precision Rail
Umbrella Corp Lower and Rifle Grip
ATF DOCUMENT USED FOR AR15 PISTOL BUILD
). 
