So…you want a black rifle to make some pews with, leading you to consider an AR-10 vs. AR-15. But you hear that one of the two flavors of ArmaLite Rifle (because that’s what “AR” stands for, after all) is better than the other. What, pray tell, is a person to do?
We HAVE to choose? Oh, alright.
The answer is that you should think about what you’re going to do with your rifle. Both the AR-10 and the AR-15 are excellent rifle platforms, but the differences betwixt them will usually mean you’re better off with one compared to the other depending on how you intend to use it.
Both rifles are the brainchild of Eugene Stoner, developed under the ArmaLite company. Stoner had an idea for a rifle system that was simple, but reliable, lightweight, but easy to control. The AR-10 actually preceded the AR-15 as Stoner and ArmaLite first created rifles chambered in 7.62x51mm for service rifle trials in the late 1950s.
The M14 was chosen instead (for a number of stupid reasons we won’t get into) but were practically obsolete on arrival in the early 60s. The conflict that our armed forces found themselves in at the time demanded a lighter rifle with a synthetic stock and an intermediate cartridge. Stoner adapted the platform for .223 Remington (standardized by NATO as the 5.56mm) and the AR-15 was born.
Both rifles were made with select fire capability for military purposes and semi-auto only for civilian sales.
ArmaLite, of course, was a small company that didn’t have the capability to manufacture at scale, so the design was sold to Colt. The AR-15 in military guise was designated the M16, which became the standard service rifle of the US military until it was replaced with the M4, which is basically the same gun with a collapsible stock, a shorter barrel and a few other features.
So, what are the differences between the AR-10 and the AR-15?
Mechanically? Nothing. Both use the same direct impingement gas system, which cycles exhaust gases from the barrel back into the receiver to cycle the bolt rather than exhaust gases actuating a piston-based system. Both also have a rotating bolt design. The trigger group is the same.
Both are lightweight, both have a pistol grip and both have an adjustable stock on most models.
Barrel length was initially the same at 20 inches, but today you’ll find that, generally speaking, the typical AR-10 you find in stores has a barrel length of 18 to 20 inches, compared to 16 for the standard AR-15.
Obviously, both fire different cartridges.
The AR-10 chambers 7.62x51mm NATO/.308 Winchester.
The AR-15 chambers 5.56x45mm NATO/.223 Remington.
What does that mean in real world terms?
The AR-10 has a longer effective range. How you define that is relative (scoped/unscoped, a 1,000 ft-lb of energy threshold) and depends on specifications (barrel length affecting accuracy and velocity, what bullet and loading you’re using) but the AR-10 is presumed to have an effective range somewhere between 600 and 1,000 yards, depending.
On the other hand, the AR-15 has an effective range closer to 300 to 500 yards, again depending on how one defines that, the rifle and load specifications and so on. In that regard, the AR-10 vs AR-15 debate favors the bigger round.
Muzzle velocity for .223 is higher, typically in the 2700 to 3200 fps range for typical loadings. Typical .308 loads push the .30 caliber pill a bit slower, with typical velocities between 2600 to 2800 fps. However, the .308 also brings a whole lot more wallop, with muzzle energies between 2500 to 2800 ft-lbs compared to 1200 to 1300 ft-lbs for garden variety loadings of .223/5.56mm.
With the greater muzzle velocity and barrel length, the AR-10 is better suited to long range use and – for lack of a better term – has more stopping power, which is kind of the crux of choosing between the AR-10 vs AR-15.
The AR-10 is a better all-arounder. In this respect, it’s actually one of the best rifle designs on the market. It’s useful for long-range target shooting out to 1,000 yards, far better than the AR-15. Since it’s lightweight but also chambers the .308 Winchester, it’s also an excellent hunting rifle. The .308 Winchester is capable of taking any game in North America short of the large bears, and much in Africa and elsewhere.
The .223 is effective on deer in expert hands and at close range. However, many jurisdictions impose a .24 caliber minimum on big game, so you’re limited to varmints and predators in many states anyway. Some believe use of .223 on game is unethical to boot…but that’s for another time.
As a military rifle, both have advantages. The AR-10 has a longer range and more – if one must use the term – stopping power, but is more awkward in close quarters. The AR-15 also offers faster followup shots, which – in a military/law enforcement/defensive capacity – matters a lot.
Depending on whom you get it from, you’ll have to shell out a little more for an AR-10. Usually, expect to part with an extra $100 to $300 for an apples-to-apples gun in 3.08/7.62mm.
The AR-15 is going to be a bit better to run for competition because the rounds are cheap(er). If the target shooting you’re doing tends to be at closer ranges (say within 300 yards) the smaller round is going to give you more bang for the buck. At that, if all you’re going to be doing is target shooting, the AR-15 is probably the better buy for those reasons.
However, if you’re after a black rifle that you can get some serious use out of with more punch, AR-10 rifles are the way to go.