Those buying their first AR-15 will come across a very confusing array of choices and options. This article is intended to simplify that process with some basic recommendations. Keep in mind that I'm not a firearms expert and not a gunsmith, but I've built a few AR-15's, competed in a few NRA High Power service rifle matches, and spent a few years in the infantry. Take my opinions and compare them to information from other sources and make up your own mind. The following applies to an all around general purpose AR-15 for self-defense / target shooting. This does not apply to special purpose rifles for match shooting, long range, etc.
You can buy a complete rifle or you build it yourself. I recommend building the lower yourself and buying a complete upper. If you want to save some money and build the lower yourself, see my earlier posts: "Building a High Quality Low Cost AR-15" and "Tools for Building an AR-15 Lower."
The lower receiver is the heart of the rifle. If you are building your own, get this first. This is the only part that you cannot mail order for delivery to your home. I would get if from your local gun shop (LGS). You could buy it online and then pay a fee to your LGS to transfer it to you, but you probably won't save much. I recommend the standard AR-15 lower without any special bells or whistles. Almost all lowers are made by one of four manufacturers and then rebranded. It doesn't matter which one you go with, but stay away from Hesse, Vulcan or Blackthorne.
As for the rest of the lower parts. Plain GI mil-spec is the way to go initially. If you plan on putting in a better trigger (more on that later), you can get a lower parts kit minus the fire control group to save a few bucks. Receiver extensions (buffer tubes) come in mil-spec or commercial varieties. The mil-spec variety uses a more expensive manufacturing process that makes it strong. The commercial is made less expensively, but with thicker metal to compensate. It doesn't really matter which you go with, except that your buttstock will have to be either mil-spec or commercial spec to match it. I recommend the standard M4 6-position collapsible buttstock. These come in both commercial or mil-spec. Magpul stocks also come in commercial or mil-spec. I don't know about other brands. I went with mil-spec just because it made me feel warm and fuzzy inside. As for the buffer, I went with the H buffer that comes with the lower parts kits that I bought. Carbine buffers have 3 weights inside. A standard buffer has 3 steel weights. An H (heavy) buffer has 1 tungsten and 2 steel. H2 has 2 tungsten and 1 steel. H3 has 3 tungsten. The buffer can effect cycling and reliability. I have had no issues with my H buffer. If you do have reliability issues, you can experiment with different buffer weights.
For the upper receiver, go with a flat top. This allows you more options later. For the rest of the upper receiver parts, go with GI mil-spec. I like plain GI style hand guards with heat shields. They are inexpensive, and they work. They don't offer a lot of options for mounting gizmos, but I don't need a lot of gizmos. You can always get a quad rail later to mount a bunch of crap.
As for barrels, I like a 16" barrel with a mid length gas system. A 20" barrel is bit more accurate at longer ranges with a trade off in handiness and maneuverability. Some people like the M4 style barrels, but they are still 16" (unless you want to go with an SBR and deal with the ATF). They have a short carbine length gas system that is not as reliable, and a bayonet won't work unless you put a a special adapter. You could get a 14.5" barrel with a pinned/welded flash hider that is ATF legal, but now you can't remove your flash hider or gas block later if you want to swap out components. I recommend a government profile chrome lined barrel. The government profile is a nice compromise between the accuracy and strength of a heavy barrel and the light but weak pencil barrel. You can get chrome moly vanadium (CMV) barrels or cold hammer forged (CHF). CHF is better, in that they last longer, but are more expensive. A standard CMV barrel will do just fine. You want a barrel extension that has M4 feed ramps for reliable feeding. You want an "F" height front site base, to match your flat top upper. Twist rate can get confusing. Most barrels these days are either 1/7, 1/8 or 1/9. 1/7 means the the rifling makes one rotation in 7 inches. Different twist rates are useful for stabilizing different bullet weights. It all depends on what ammo you are going to use. 1/9 is better for the cheap 55 grain bullets, but not so great for heavier bullets. 1/7 is better for 62 (green tip) to 77 grain (match grade) bullets. 1/8 is a compromise between the two, and the best bet for a general purpose rifle. 1/7 is not a bad choice, but you may have accuracy issues with 55 grain rounds. You want a rifle chambered in 5.56 not .223.
The bolt carrier should be a full auto profile (the ATF won't hassle you for this) and chrome lined. The full auto profile carrier is heavier and cycles better. The gas key should be chrome lined, hardened, have grade 8 fasteners, and be properly staked. The bolt should be Carpenter 158 steel, shot peened, high pressure tested (HPT) and magnetic particle inspected (MPI). The bolt and carrier take a beating. These features help ensure that it doesn't break when you need it.
Now for accessories. A rear sight should not be considered an accessory, but a lot of so-called "complete" rifles don't have one. No big deal, this allows you more flexibility to choose your own. I like the standard mil-spec carry handle with A2 style sights. Learn the basics of marksmanship with iron sights before you go and buy the latest gee-whiz optic. A Meprolite tritium front site post will allow you to aim in the dark. A GI loop sling is a great starter sling for learning marksmanship fundamentals. If you don't know what I'm talking about, look for the one my by CJ Weapons that Midway sells. This is the same sling that Appleseed recommends. Another upgrade to consider is a better trigger. I recommend the ALG Defense advanced combat trigger. It is a standard single stage GI type trigger, but better quality. Crisp break and no gritty feel. I have heard that Velocity Triggers are good, but they are also more expensive. I have not used their product, so I cannot vouch for it personally. If you want to mount a flashlight, Hot Shot makes a magnetic mount that lets you mount a standard tactical light, like a SureFire. It doesn't require any kind of mounting bracket. Bravo Company makes an extractor spring upgrade kit. People say it increases reliability. I drank the Kool-Aid and bought it. My rifle fired just fine before and after. Does it help? Maybe, but I'm only out $5.
I almost forgot magazines. You can't go wrong with the Magpul M2 MOE 30 round magazine. I've never had a problem with these mags and they can be found for $10-12 each. The M3 is supposed to be better, but a little more expensive. Since I've never had an issue with the M2, and they still make it, I'm sticking with it. I've never had use for the mags with windows. If you have GI aluminum mags, upgrade them with Magpul followers. This improves reliability by not allowing the follower to tilt.
He is a summary of recommended specs:
Lower - anything but Hesse, Vulcan, Blackthorne
Lower parts - mil-spec (minus fire control group if getting ALG trigger)
Receiver extension (buffer tube) - mil-spec (or commercial)
Buttstock - M4 6-position (mil-spec or commercial to match the receiver extension)
Buffer - H
Upper - flat top
Barrel - 16", mid length gas system, 1/8 twist (2nd choice 1/7), CMV (or CHF), chrome lined, GI profile, 5.56 chamber, M4 feed ramps, F height front sight base
Hand guards - standard GI
Bolt carrier - full auto profile, chrome lined, hardened chrome lined gas key, grade 8 fasteners, properly staked
Bolt - Carpenter 158 steel, shot peened, HPT/MPI
Rear sight - standard GI carry handle with A2 sight
Accessories / Upgrades
Magazines - Magpul M2 MOE (
CJ Weapons GI web sling
Meprolite tritium front sight post
ALG Defense advanced combat trigger
Hot Shot magnetic flashlight mount
Bravo Company extractor spring upgrade kit
Optics - Learn the basics of rifle marksmanship with iron sights first, then do your own research.
Recommended sources:
Palmetto State Armory
Midway
Brownells
