A common question I hear is “What AR-15 should I buy?” This might come from a gun owner new to the platform or someone looking to get more ARs. But fear not! Parvusimperator is here to answer this question for you. For both the new gun owner, and the guy looking to expand his collection, the right answer is the Colt 6920.

Why Colt? Why this old-school looking gun? Why not something cheaper like a DPMS? Why not something with more features people want these days like a ‘mid-length gas system’ or ‘mile-long handguards’?

We’ll get to those. First, a brief bit of background. Don’t worry, it’ll be relevant, I promise. Eugene Stoner developed the AR-15 as a follow on to the AR-10, a lightweight competitor that lost out to what would become the M-14¹ in the US Army’s competition for a rifle in the new 7.62x51mm caliber in 1957. The AR-15 was designed to use a small-caliber high-velocity round to maximize controllability when firing fully automatic and to be easy to aim across the ranges that infantry combat was generally expected to take place at.² Anyway, both designs were cooked up while he was working at Armalite, hence ‘AR’, which stood for Armalite Rifle. Armalite was a small company out of Hollywood, California, and it was made to apply the latest high tech aerospace³ materials, like forged aluminum and fiberglass, to the firearms industry. The AR-15 was developed for a contract for the US Air Force’s airbase security forces, but Armalite didn’t have much in the way of manufacturing capability on their own. So they sold the design and the rights to it to Colt, who had plenty of arms manufacturing capability.

This means Colt has what’s called the Technical Data Package, or TDP. It’s the plans for the gun in the sort of nauseating detail that only engineers can appreciate. Materials list, dimensions, and crucially, tolerances. Colt has been forced to send this TDP out to other manufacturers for the process of making M4s for the US Military, but those other manufacturers are contractually forbidden from using the TDP to make guns for civilians. So only with Colt are you getting everything as you’re supposed to be. This is most important with little things involving tolerances. Everyone else can reverse engineer the dimensions, but tolerances are harder to come up with if you don’t have the plans. Which means Colt rifles are going to have a correctly sized gas port,⁴ among other things.

Colt makes M4s for the Army, and given the desire to not fuck up this crucial contract, they’re going to make them right. So they’re going to make your rifle right too, because it’s not worth the trouble to set up a whole new production line. What does this mean for you? Well, it means that all the critical fasteners, specifically the castle nut and the screws for the gas key are going to be properly staked. Staking is deforming a little bit of metal to prevent something from backing out. You could “just use loctite” on the castle nut, I suppose, though those threads are a trifle fine and not really suited to it. Loctite won’t work on the gas key screws though, since that’s where a ton of heat is going. And if those screws come undone, you’re gun is junk. And fine, on the range, that’s just annoying. But it could mean you’ve lost a match. Or, if you’re using the gun professionally, you could end up deader than Elvis. Don’t end up a dead loser. Stake your gas key screws. Which Colt does for you.

You’re also paying for that US Military grade QC with Colt. Which means a Colt rifle is less likely to have out of the box issues. They build their carbines right and inspect every one.

All that said, there are some downsides. The 6920 has exactly two differences from an issue M4. First, it’s got a 16″ barrel to comply with the damnable NFA laws about barrel length. Second, there’s no burst fire/autofire functionality. Those are the only differences. This means the stock is pretty basic, the pistol grip is that infernal A2 jobber that I hate, and you get boring round handguards. Fortunately, the stock and pistol grip are easy to swap out, and that’s fine, because those are intensely personal choices. The handguard contains two heat shields, as is right and proper and standard issue. But it predates all those cool accessories, and it’s not free float⁵. You also get a fixed front sight block. On the one hand, that’s good, because it’s held in place with two pins. It isn’t going anywhere. On the other hand, that’s going to get in the way of all kinds of handguards you might like to mount.

So even though I’d caution that the stock handguards handle heat of a good extended shooting session very well, and you probably don’t need to attach a ton of crap to your carbine, and that the free float obsession is silly, and that the money spent on a fancy handguard might be better spent on ammo or a class or a good optic, you’re still gonna want one. No problem, I’ll enable you and tell you how to make it work. You’re almost certainly going to need to remove the stock barrel nut, or at least the delta ring and handguard cap, which is going to entail removing the FSB among other things. No problem. When you’ve removed the FSB, you can actually cut the sighting portion off with a hacksaw, file/dremel it to fit under your new handguard without spoiling the gas-collecting bit, and then refinish it with some grill paint. It’s so easy a caveman can do it. Seriously, it’s super easy. Don’t worry if it doesn’t look professional, it’s going to be under a handguard anyway. Make sure it fits, don’t cut the gas part open, and you’re fine.

Colt even will oblige you by doing this from the factory on the 6920 OEM2 model. This rifle ships with no stock, no handguard, no delta ring, no handguard cap, and no trigger guard, so you can swap these parts out yourself. The gas block is cut down and reparkerized from the factory. (This is a nicer way to do it than using grill paint, but grill paint is way easier and cheaper for the amateur). The OEM2 model still has the A2 handguard, because that holds in the spring and detent for the safety, so it has to ship with something there.

As for midlength gas, I don’t get the fuss. The rifle and carbine length gas systems are proven with an absolutely ridiculous number of rounds. It will work. Always. Midlength seems to work too. It’s not as proven. It might be “softer shooting”, but that’s very subjective. Plus, we’re talking about 5.56mm here. This is not an elephant gun. This is an easy rifle to shoot. Really. It is. And just in case, you can always add a comp to reduce muzzle rise that little bit.

So, what have we learned today, class? Stop overthinking it. Stop worrying about it. Just buy a Colt. And ammo. And quality mags. And get some range time.

1.) It’s still probably the best battle rifle of the era on a technical basis, but that’s another story.
2.) For more on small caliber high velocity rounds and why they’re great, see here.
3.) Armalite was funded by Fairchild Aircraft. Back in those days, California manufactured actual things like airplanes, and not just stupid.
4.) Colt does not drill out a giant gas port so that your gun will function correctly with crap ammo. The US army doesn’t use the worst reman and lowest quality dumping ground ammo. Maybe you shouldn’t either.
5.) Insert loud sigh here. I don’t understand the obsession with free floating for 95% of rifle shooters. Most people shoot at a range of 100 yards or less, with at best milsurp M855 or M193 ammo, or possibly that underpowered crap I mentioned above, at targets rather larger than a man’s torso, but god forbid their handguards touch the barrel. Seriously, it doesn’t matter. There are more important things to worry about and bigger fish to fry, like proper technique and practice. And if you’re sitting on a bench trying to split a gnat’s ass at 100 yards with your entry-level carbine and cheap chinese knockoff optic, you’re also being dumb. Get off your butt.