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Wednesday, August 8, 2012

Pint-sized Powerhouse: My Palmetto State / Doublestar 7.5" AR 15 Pistol Project

Addictions come in many flavors:  mine just happens to be gun collecting.  Firearms find their way into my collection for various reasons.  There are some guns that I desire due to their historical significance.  Others, I seek out because they are examples of fine workmanship, exceptional engineering, or both.  Still others have been selected due to their utility for self-defense, hunting, target shooting, etc. -  my "working guns," as it were.  And finally, there are what I consider my "fun guns":  firearms that I simply find entertaining - plinkers and the like.  And my newest acquisition falls into this last category.

I say "acquisition," but that is not technically accurate, as this particular firearm is one that I built from parts.  The first gun that I built completely from parts, actually... an AR 15 pistol.  This particular build has been in the works for quite a while:  I have been picking up pieces here and there for nearly a year. There seemed to be no rush to complete it as I originally conceived of this gun simply as an exercise in "kitchen table" gunsmithing.  However, as recent events have thrust the possibility of new gun control legislation into the spotlight, and with this being an election year, I decided that I should go ahead and finish this gun while I still had the opportunity.

AR-style pistols are nothing new, and you will find them in several different calibers.  For this project, I decided to stick with the traditional 5.56mm chambering, even though you will find many detractors who ridicule the use of this rifle cartridge in such a short barrel.  And to be honest, their arguments are not without some merit.  The 5.56mm cartridge was originally designed to be used in a rifle with a barrel 20 inches in length.  Any less than this length reduces the efficacy of the cartridge.  Now, it seems the majority of AR models on the market today are based on the 16 inch carbine barrel, a length that generally produces adequate ballistics.  As you decrease the length of the barrel, however, not only do you rapidly lose velocity (and hence energy), you also decrease the reliability of the weapon:  the AR direct impingement gas system does not operate as smoothly when it is shortened.  The short barrel does not allow the pressure in the gas tube enough time to act on the bolt in the same manner it would in a longer barrel.  The trick to getting an AR pistol to run reliably requires experimenting with springs, buffer weights, etc.  Thus, the loss of energy (affecting fragmentation of projectiles in the target) and potential loss of reliability are factors that must be considered.

After weighing my options, I decided to stick with 5.56mm for two main reasons:  first, if I am going to have an AR, I want it to be in that caliber, as that makes it compatible with my other AR, and thus parts and accessories can be shared; and second, it allows me the option of running a .22LR conversion kit, thus making this a much more affordable range gun.  And if, God forbid, I should ever have to use this gun in a defense role (it would probably fall way down the list of my options), it would still have enough "oomph" to get the job done.

This build started with an A2 upper that I happened to have lying around, waiting to be assembled.  I really like the look of the A2, with the built-in carry handle...  it is to my mind what an AR-15 should look like (one man's opinion, true, but hey, this is my gun we are talking about).

A2 upper receiver
(image courtesy of ar15.com)
For a lower receiver, I bought a stripped lower from Palmetto State Armory.  Occasionally, you can get a great bargain on these lowers, and I bought mine on sale for $49.99 last Valentine's Day.  A fantastic deal on a fantastic lower.  Note:  when building an AR pistol, it is extremely important that you use either a lower designated as a pistol lower, or a "virgin" lower that has never been assembled as a rifle.  If the lower has ever had a buttstock attached, (even if it is clearly labled "pistol" on the receiver) you may not use it to build a pistol without running afoul of the NFA regulations.  You should always check to make sure that the lower was transferred to you as "pistol" or, (preferably) "other," not "rifle," before using it for a pistol build.

PSA Stripped Lower Receiver
(image courtesy of palmettostatearmory.com)
This being a stripped lower, I required a lower parts kit to finish it.  I decided to go with the DPMS kit, as I had heard good things about them, so this I picked up from Tri-Cities Gun Depot.

DPMS Lower Parts Kit
(image courtesy of surplusammo.com)
As I was assembling a pistol, I decided to go with the Doublestar Arms carbine-length pistol buffer tube.  The research I had done indicated that the longer buffer tube and spring was less prone to malfunction and required less fine-tuning to operate reliably.  This I picked up from another local gunshop, Gunslingers, in Kingsport, TN (a fantastic place for AR fans...  they have just about anything you could need or want).  I also swapped out the standard pistol buffer for an H2 buffer, as the data seems to show that 7.5" pistols run more smoothly with the heavier buffer.

Doublestar Arms Pistol Buffer Kit
(image courtesy of jsesurplus.com)
I also decided to go with the Magpul ASAP ambidextrous single-point sling adapter, which I picked up at Tri-Cities Gun Depot, as well.  I like how it allows the sling to move freely to either side of the weapon.

Magpul ASAP
(courtesy of del-ton.com)
To finish the upper, I ordered a pistol-length gas tube with roll pin, and a Yankee Hill Manufacturing Mini Free Float Tube Forearm from JSE Surplus.  Since I would not be adding a vertical fore grip (another NFA no-no), I decided against a railed handguard, and instead went with the more rounded tube from YHM, which is also very light-weight as well.

YHM Mini Free Float Tube Forearm
(image courtesy of galatiinternational.com)
For a barrel, I again chose Doublestar Arms, and ordered the 7.5" Heavy Profile Barrel with Forged Sight Base from J&T Distributing.  It did not come with a barrel nut (almost all 7.5" ARs are fitted with free float tubes... in fact, I do not know where you would find a standard 2-piece handguard that short), but has M4 feed-ramps, and you can choose to have it chrome-lined for an additional cost (I went without chrome-lining...  just a personal preference).

Doublestar Arms 7.5" AR Pistol Barrel
(image courtesy of jtdistributing.net)
One reason I went with the Doublestar barrel is that I had also picked up a Doublestar bolt carrier group and charging handle at Gunslingers.  I know that most reputable manufacturers turn out parts that meet the industry standard for specs, but I always like to get a barrel and BCG from the same company when I can.  Sticking with the "evil black gun" look, I chose the phosphated BCG, rather than a chrome group.

Doublestar Arms Bolt Carrier Group
(image courtesy of tacticalar15s.com)
And to finish it out, I decided to go with the Levang Linear Compensator as my muzzle device.  I have read a lot of good stuff about this comp from other pistol builders.  One of the issues with the AR15 pistol is that there is a LOT of unburned powder that makes it out the end of that short barrel, resulting in a tremendous muzzle flash, and the noise and concussive force produced by firing the gun can be overwhelming.  The Levang Linear Comp addresses this by directing this gas, noise, and force forward away from the shooter, thus making the gun more shootable.

Levang Linear Compensator
(courtesy of parallaxtactical.com)
Put all of these parts together, paracord wrap the pistol buffer tube for added comfort when getting a cheek-weld, throw in a Magpul 30 round P-mag,  and the end result is one pint-sized powerhouse - the AR15 pistol.

Say "Hello" to my little friend!!
I will update this post when I have a chance to get it out and shoot it.  Not looking for any sub-MOA groups with this little one, but I imagine it will be a BLAST at the range!!  And if there are any other AR pistol enthusiasts out there, tell me about your builds...  I would love to find out what your setups are.

Oh, and one final thought:  to all of the gun forum sages out there who are so quick to denigrate the AR pistol, the .500 S&W, the Barrett .50 caliber rifle, or any other firearm, as impractical, useless, excessive, or unnecessary...  these are the same arguments that those who would take away all of our guns have been using for years.  Let us not give these people any more ammunition by turning on one another.  Do I have a need for a .50 caliber Barrett?  No.  I would love to have one for the collection, but it will probably never happen for me (no offense, Ronnie...  you make wonderful guns, but I cannot afford to feed one).  But that does not mean that they should no longer be available to those who would have one.  Just like a two-seater convertible - practicality is not the end-all-be-all.  The Second Amendment says "shall not be infringed," so let us try our best to keep it that way.