Monday Gunday Guestpost: Building an AR

Today's guest post is by ZerCool, a gunnie and fellow blogger. 


Greetings and permutations, kids. I volunteered to write a guest post for Erin, and foolishly left the topic up to her. I was given the following topic:

"Something about building an AR, perhaps? It's something I'm trying to do and you have experience with."

Well, at least she didn't ask me to write about Ponies. That'd be the shortest guest post ever...

ZerCool things he's all badass, but he built this AR for his wife.
It's called the Delicate Flower. This is the rifle a pony would use.

The beauty of the AR platform is its inherent flexibility. It's been called "Legos for grownups" and "Barbies for men" and neither one is a bad comparison. (Editor's note:  I have been informed that it is impossible to spell "Barbie" without "AR".) The rifle separates into two halves (conveniently called "upper" and "lower") by pushing out two pins. Very few special tools are needed to do depot-level maintenance or assembly on an AR, and even fewer for assembling the lower - the actual "firearm".

This is a stripped lower receiver; the only piece of an AR that requires an FFL be involved.

There are plenty of quality manufacturers out there and a few not-so-good. The bottom line to look for is a forged, mil-spec receiver. (Cast receivers exist and have a higher potential for flaws; avoid them.) York Arms is a personal favorite, because of options for custom serial numbers and markings - but you'll pay a slight premium for that level of service. Expect to spend $100-150 for a lower. (There are other options out there known as "billet" lowers which are twice as expensive and provide some other options - prettier lines, colored anodizing, etc. A good example is Seekins Precision.)

Once you've got a lower in hand, you need a Lower Parts Kit (LPK). This contains all the springs, pins, catches, and so forth needed to transform the paperweight of a stripped lower into a "complete" lower. LPKs are generally about $60 and will included a generic trigger and hard plastic A2 pistol grip. Assembling the parts kit requires a pair of pliers, a gunsmithing hammer (I have a Shooboy Hammer, which can be ordered from the user of the same name over at the S&W Forum. It's worth every penny.), a screwdriver, a bit of masking tape, and ideally a set of pin punches. I use the Lower Assembly Guide on AR15.com every single time - I just don't build enough lowers to not need the instructions anymore. Have a clean work space with good light. Give yourself some time, work carefully, and in an hour or two, you should have a complete lower (less the buttstock).

The trigger included with the parts kit, unfortunately, tends to - for lack of a better term - suck. Grit, creep, overtravel, heavy - you name it, there's a stock trigger that has some or all of those characteristics. There are plenty of aftermarket upgrades from companies like Rock River Arms, Timney, Geissele, Chip McCormick, and on and on. Try the stock trigger before you jump on one of those; you may find what you have is acceptable for your use.

Now comes the fun part: deciding what you want to do with the rifle. Hunting? Home defense? Plinking? Precision? Big game? Each of those is a new upper and two pins away. An upper can be had found in every caliber from .17 HMR to .50 Beowulf, although the most common chambering is 5.56x45/.223 Rem.

Defending your home? Consider something in 5.56 or 300 BLK. Hunting predators? .204 Ruger or 5.56. Big game? 300 BLK, 6.8 SPC, .458 SOCOM, .450 Bushmaster, or .50 Beowulf may all prove to be good options. Plinking or fun at the range? .22LR or 5.56 are perfect.

Add the stock and buffer of your choice, some kind of sights... and you're off to the races.

Yeah, I didn't follow all of that, either. But look at this pretty rifle! It even has a cutie mark!