A few more notes on the AR-15 platform


Readers have asked a number of questions about the AR-15 rifle and/or carbine platform since my article on Tuesday titled “Can a cheap, bargain-basement AR-15 keep up with a high-end model?”  A number of them related to the difficulty of obtaining rifles of known quality or provenance, particularly in times of widespread shortages such as this.

First off, let me refer readers to the three-part series on this subject that I wrote earlier this year:

  1. The personal defense rifle, part 1: a few thoughts
  2. The personal defense rifle, part 2: reader’s questions
  3. The personal defense rifle, part 3: choosing ammunition

Those articles covered most of the questions.  For the rest, here goes with some more answers.

1.  An AR-15 has two major parts, an upper receiver and a lower receiver.  What’s the difference, and which is most important?

The lower receiver is the part of the AR-15 that’s officially a “firearm”, according to Federal law, and is the part that requires a background check when you buy an AR-15 from a dealer.  It contains the trigger mechanism that fires the gun, and without it the gun can’t fire:  therefore it’s the licensed, registered part.  The serial number appears on it (usually engraved or stamped on the magazine well).

A lower receiver is, oddly enough, the least important quality concern when it comes to building an AR-15.  As long as you have a stripped (i.e. bare, unequipped) lower that meets military specifications (so-called “mil-spec”), including dimensions, materials and quality, you’re good to go.  It’s the parts you put into the lower receiver (pins, springs, and most importantly the trigger group) that make it high- or low-quality.  Most AR-15 “home-builders” or modifiers (like myself) source their lower receiver parts kits from decent-quality manufacturers, so there are seldom any issues with them.  (That’s exactly what factories do, too, except that they buy their parts by the thousands, whereas we buy them one or two at a time.  They come from the same sources.)

For example, my local gun shop currently has a dozen or so parts kits from Anderson Manufacturing – a lower-priced manufacturer – on its rack, and they’re selling like hot cakes.  Anderson makes hundreds of thousands of AR-15 rifles, carbines and parts kits every year, so if their parts didn’t work or broke, you’d hear about it in short order from tens of thousands of angry customers.  You don’t.  Q.E.D.  That doesn’t mean that their parts are all necessarily high-quality.  Their trigger, for example, is acceptable, but far from stellar.  I usually replace them (see below for more details).

The one really important variable in the lower receiver is the trigger group.  A stock-standard mil-spec trigger is acceptable, but not much more than that.  A “tuned” or “polished” standard trigger is somewhat better.  A custom trigger can be head and shoulders above that . . . but the law of diminishing returns applies.  You can spend a little more and get a big improvement in trigger quality;  but if you spend much more, you won’t necessarily get a much bigger improvement.

In the past, I’ve recommended the single-stage ALG Advanced Combat Trigger ($69), or for those who want maximum accuracy in a designated-marksman-type rifle, the two-stage LaRue Tactical MBT-2S ($80).  I recently put two rifles in front of a friend, one fitted with the LaRue trigger, the other with a Geissele trigger costing more than three times as much.  I challenged him to tell me which was the more expensive (and therefore presumably “better”) trigger.  He couldn’t.  They were both very good.  That being the case, I don’t think it’s worth spending more than the ALG or LaRue units will cost you.  I have both.  For my general-purpose rifles I stay with the ALG.  For two very accurate rifles, that I may use at longer range and therefore want as much trigger control as possible, I use the LaRue.

The upper receiver is, according to Federal law, not a firearm.  You can buy it without any license or background check (at least at present).  It holds the barrel, bolt carrier group, and everything that goes with them (sights, both optical and mechanical;  anything attached to the handguard, like lights, lasers, etc.;  brass catchers;  etc.).  Its components are therefore critical to accuracy, as much as reliability, and you should choose the best you can.  I know a large number of people who’ve bought or built the best-quality upper receiver group they could afford, then paired it with a much less expensive mil-spec lower receiver.  The performance of the upper receiver isn’t affected by the lower, so the performance of the rifle overall doesn’t suffer – and they save a lot of money.  I’ve done that with a Bravo Company 20″ upper receiver group, which I’ve paired with a DPMS lower receiver fitted with a high-quality match trigger.  That thing’s a tack-driver by anyone’s standards (under 1 MOA with match ammo), and it cost me about two-thirds of what Bravo Company wanted for a full rifle.  It’s what I could afford at the time, and I’ve never regretted it.

The basic upper receiver should meet military specifications as to dimensions, quality of metal, etc.  Some go further.  For example, Bravo Company (one of the top AR-15 manufacturers in the country) is famous (or notorious!) for making its upper receivers to such tight tolerances that it’s really hard work to fit a new barrel to them.  One has to take a heat gun, warm up the barrel socket until it expands, fit the barrel into it (usually needing a hammer, lubrication, and a liberal supply of profanity), and then let the socket cool down around it, locking it into place.  That’s one of the reasons why Bravo Company rifles, receivers and parts command such high prices.  Their reliability and build quality are well-known and respected.

Barrels are, of course, particularly important (for an exhaustive guide to barrels, see here and here).  A standard mil-spec barrel, made to meet US military standards, has to shoot its rounds into a 5″ group at 100 yards (colloquially referred to as “5 MOA” [minute of angle], although that’s not correct, strictly speaking, in purely mathematical terms).  I regard that as hopelessly inadequate.  If one of my rifles won’t shoot into 2″ at 100 yards from a stable shooting position, I either fix it or replace it!  The military barrel also has to last for at least 6,000 rounds before needing replacement.  That’s not as much as it sounds:  it’s the equivalent of only 200 30-round magazines through the weapon.  Just about any commercial barrel will meet those standards, and anything worth the name will be much better than that.  Of course, the better barrels will cost more;  I’ve paid up to $300 for good-quality examples, and if you go to a custom barrel-maker, you can pay well into four figures for one.

The bolt carrier group (BCG) is also important from the perspective of reliability.  A cheap BCG will have a rougher finish (usually phosphate), requiring more lubrication to be reliable.  More expensive BCG’s will have a black nitride or nickel boron finish, or even (in the most costly examples) a titanium nitride coating.  These slide more easily in the upper receiver, and need less lubrication.  (See here and here for more information on BCG coatings.)

A BCG (or representative examples from a production batch) should go through a high-pressure test (HPT) and a magnetic particle inspection (MPI).  The gas key should also be properly staked, and the extractor spring good and strong.  I willingly pay higher prices for BCG’s from reputable manufacturers, rather than bargain-basement models, because those companies take time and trouble to meet those standards.  However, any company selling large numbers of BCG’s will be forced to pay attention to quality, because if they didn’t, they (and we) would rapidly hear about it from dissatisfied customers.

2.  In today’s gun market, I can’t find any “name-brand” AR-15’s for sale in local gun shops.  Should I buy anything I can get for now, and buy a better one later?  Isn’t that throwing my money away?

It depends on your need.  If you’re likely to need a rifle or carbine for defensive purposes (e.g. you live in or near an area of urban unrest or rioting, or there are criminal gangs active nearby), then your priorities are very different from someone living on a farm in an isolated area with no likely trouble spots anywhere nearby.  If time is of the essence, get the best you can, and plan to upgrade it later – not necessarily selling it, but buying better parts like an improved trigger, etc.  If the budget is tight, sure, trade it in against something more to your taste.

It’s also important to test your weapon thoroughly at the range.  I know some folks who buy a gun and never shoot it.  They simply load it and put it away in case of need.  If it’s not the best quality, and may be prone to malfunctions, they’ll only find out about it when they really need it – and that may be too late to do anything to fix it.  Rather take your gun to the range and put a couple of hundred rounds through it, to break in and bed down all the moving parts, and make sure there are no malfunctions.  If there are, take it back to the vendor and insist that it be fixed or replaced.  Your life may depend on it!

If you can’t find an acceptable-quality AR-15, don’t neglect other options.  Lever-action rifles have been defending lives (as well as putting meat on the table) for more than one-and-a-half centuries, from the Civil War-era Henry and Spencer rifles to today’s Winchesters, Marlins, Henrys and others.  The late, great Jeff Cooper referred to a lever-action rifle or carbine as a modern-day “urban assault rifle“, because of their handiness and utility.  You can usually get a license for them in even the most restrictive cities, and they do a very good job within their limitations.  I have several, and I’ll gladly entrust my life to them if I have to.  Other options are pump-action (also known as slide-action) rifles, shotguns, etc.  I agree, the AR-15 platform is a very good one for defensive use, and I prefer it:  but if I couldn’t afford one, or find a worthwhile example for sale, I wouldn’t be helpless without it.

3.  The incoming Biden administration has promised to ban, confiscate or tax AR-15’s.  Doesn’t that mean it’s not worth buying one?

I’m not going to tell anyone to break the law.  That’s a personal decision each of us has to make.  However, I’ll point out three things.

  1. For almost as long as the USA has existed, and particularly during the Civil Rights era, civil disobedience became part of the American political and legal lexicon.  Laws were deliberately defied if they were seen as oppressive or discriminatory.
  2. When New York passed its “NY SAFE Act” in 2013, requiring the registration of all so-called “assault weapons” (including AR-15’s), civil disobedience was – and remains – massive.  “Based on an estimate from the National Shooting Sports Federation, about 1 million firearms in New York State meet the law’s assault-weapon criteria, but just 44,000 have been registered. That’s a compliance rate of about 4 percent.”
  3. When Connecticut passed new gun control legislation in 2013, the same thing happened.  “The governor’s new gun law is a dismal, unmitigated failure.  According to figures recently released by the state police, approximately 50,000 out of an estimated half-million “assault rifles” in the state of Connecticut were registered under the new gun law.  That is a compliance rate of only about 10 percent … The figures are even more acutely low for large capacity magazines. The compliance rate for large capacity magazines appears to be considerably less than 1 percent of the estimated number of affected magazines.”

Does anyone expect a national ban or registration requirement to be any more successful?  I certainly don’t!  Furthermore, the number of gun owners I’ve heard loudly lament the “terrible loss” of all their so-called “assault weapons” and large-capacity magazines in an “unfortunate boating accident” must surely mean that the bottoms of most US dams, lakes, rivers and streams are now several feet deep in firearms!

I’ll also point out the well-known proverb from the days of the Old West:  “I’d rather be judged by twelve (i.e. jurors) than carried by six (i.e. pallbearers at my funeral)”.

I hope that clarifies the questions I was asked.  If you have more, let us know in Comments, and I’ll try to answer them.



  1. How about less expensive manufacturers like Windham for those who do not wish to build a rifle? They offer both metal and carbon fiber receivers.

  2. @suburban: I've never owned a Windham, but I've heard good things about them. I'd rate them as acceptable quality for a defensive firearm; perhaps better than the low end, although I can't speak from personal experience.

  3. mirrors what I've seen for the most part. i would add to look inside the bolt carrier and note the smoothness and if its chrome lined or not. even some name brand makers are scrimping on that. we have over 100 rock rivers that eat gas rings like Cheetos b/c the carrier is rough inside. we have 500 fn's on the other hand that came smooth as glass from the factory. not impressed overall with rock river for a multitude of reasons.
    i'm not too concerned with triggers. my feeling is when most folks need to use one they'll be jerking the crap out of it anyway. so as long as it goes bang every time its fine. i have had some big name expensive triggers fail to go bang after some use so beware. for self defense/combat the stock ar15 as designed is more than adequate, imnsho. opinions are like rectums, everybody has at least one.

  4. I built a rifle from a Rock Island kit years ago because it was what I could afford at the time. It has never failed to send lead downrange upon command and I have a put a fair number of rounds through it. I have, therefore, never been tempted to trade it in on a "better" model.

  5. +1 on the ALG and LaRue triggers. I'm an RSO at a local range and we see a lot of folks new to the AR15 platform. They're generally easy to pick out since they know little or nothing about the platform. Not knowing how to lock back the bolt is a dead giveaway as is the $30 red dot. I've "fixed" short stroking rifles simply by lubing the bolt carrier. Sometimes I feel more like an instructor.

  6. Dunno but any time I have been an RSO I have had to instruct as well. Lots of people either do not know range safety rules or ignore them completely.

  7. +1 on the "once you get out of the el cheapo price range the law of diminishing returns kicks in quick." If you're not routinely putting at least a hundred rounds a week downrange (and that's a low-ball estimate), your accuracy issues are almost certainly your problem, not your rifle's.

    Buy mid-range, and take the money you would have shelled out for the high-end stuff and buy ammo with it.

  8. The difference seems to come down to the barrel. Install a good quality HEAVY barrel and you are good to go. Forget the crappy M4 contour. It was developed to allow for mounting an M203 grenade launcher. It is the worst of all possible worlds as a barrel.

  9. Windham Weaponry was started by the guys from Bushmaster after that firm was bought out. They make first rate firearms – second to none.

  10. An important inspection point is to check for barrel extension overhang at the upper receiver feed ramps. It's far easier to check and correct this while building the upper. If the feed ramps need to be matched, you will need a rotary abrasive tool and a delicate touch. Don't hurry-speed costs here too. Don't try this with any files you care about.

  11. On triggers – I've had very good luck with the Timney line in multiple long guns. The AR-15 Timney was a breeze to install, and was very nice when compared to the standard trigger it replaced. Another inexpensive upgrade to a firearm is to buy the Ruger-branded match trigger for your 10/22. I launched parts of my original trigger into orbit one night, and a drop-in replacement was easier than buying a new spring and other fiddly bits for the original. The result was a very crisp trigger for not much money.

  12. The big problem with calling an AR lower a receiver is that it does not meet the statutory definition of such in the '68 GCA.

    A former ATF agent who spent years complaining to his superiors in the tech division is now making consultant money testifying in court.

    He has gotten four convictions overturned so far. heh.


  13. @Kristophr: You're right, but that's only the final resolution of the issue. Prior to that, you can still be arrested, charged, and have to defend yourself (at great expense) in court. The ATF and other agencies count on most people not being able to afford either the inconvenience or the cost, so that they simply hand over their property and write it off. Those who can afford to fight that can probably win – but that's not many of us.

    That's how the ATF and other agencies get away with so much borderline illegal conduct, and why the ATF's arbitrary and capricious legal "definitions" (which are subject to change over time, apparently) are so difficult to work with.

  14. I've heard loudly lament the "terrible loss" of all their so-called "assault weapons" and large-capacity magazines in an "unfortunate boating accident"
    Not me. I recently sold the last of my semi-auto weapons – going strictly black powder. I just hope the last buyer is better than the others. Over time, I have seen all their names on left-wing comments on local news facebook sites (verified it was them as the only thing on my state's court cases site was their divorce, which lists their address), or they turned out to be left-wing politicians. Darn, I'm such a bad judge of character Mr. ATF agent.

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