Wikipedia calls it:
The AR-15 is a lightweight, 5.56 mm, magazine-fed, semi-automatic rifle, with a rotating-lock bolt, actuated by direct impingement gas operation or long/short stroke piston operation. It is manufactured with the extensive use of aluminum alloys and synthetic materials.
The AR-15 was first built by ArmaLite as a selective fire assault rifle for the United States armed forces. Because of financial problems, ArmaLite sold the AR-15 design to Colt. The select-fire AR-15 entered the US military system as the M16 rifle. Colt then marketed the Colt AR-15 as a semi-automatic version of the M16 rifle for civilian sales in 1963.[8] The name "AR-15" is a Colt registered trademark, which refers only to the semi-automatic rifle.
For purposes of this post, I'll call it 'the rifle".
So how do you start building the rifle?
With this part - the "stripped lower".
This is the part that is classified by the ATF as the actual gun. This part will contain the trigger/hammer assembly, the safety, the bolt catch, and will accommodate the magazine and the buffer tube.
This part is manufactured following the original specifications (from the 60's) for the military version of the gun. The major difference is the military version (M16) has a "selective fire" option which allows automatic fire. The civilian version (AR15) does not. All manufacturers use exactly the same specifications for the part, dimensions and material. This makes for a huge source of lowers for the consumer, but also a choice. For example, there is virtually no difference between a $65 stripped lower made by ABC compnay and one that costs $185 - they're all made to the same specifications. Just depends which "name" you want people to see on the side.
The part I bought is manufactured by Delaware Machinery. Fit and finish is beautiful, anodized aluminum. $65
Now, this is where it gets interesting...
To build out the lower, you need a trigger/hammer assembly, springs, pins, a grip, a buffer tube, and a stock. And of course, you can customize every one of these parts. I chose to buy the "standard parts", predominantly because of availability but also due to cost. My target price on this rifle is <$600.
I chose the standard lower parts build kit from Palmetto State Armory - $109. Here's what you get for the money. Note: the stripped lower is not a part of the kit.
With some trial and error, I was able to get all the parts in place in about 45 minutes. The lower build kit I bought does not come with instructions or even a schematic - I found both on the internet. There are dozens of sources for schematics and hundreds of YouTube videos showing how to assemble the various parts of the lower. At least 10 minutes of the 45 was spent searching for the information. Once you know where the parts go, it's pretty simple to actually install them.
Here's where I am now with the parts installed:
Next step: find and purchase a complete upper (barrel, upper receiver, bolt carrier group, and charging handle). Stay tuned.
