The AR-10s and AR-15s are both among the most reliable, modular, lightweight, and versatile semi-automatic rifles on the market, but if you’re trying to decide between the two, the answer will largely depend on your specific needs as a shooter. To help you narrow it down, we’ve put them head-to-head to highlight the strengths of each platform. While there are a large amount of AR15 and AR10 calibers, we will primarily be considering 5.56/223 and 308 in this article as they are the most common and widely available calibers.
A few distinctions about the naming structure of these rifles before we get into the meat of the topic.
Contrary to popular belief, in both AR-15 and AR-10s AR does not stand for “assault rifle”, but rather it means Armalite Rifle, named after the company that originally developed and produced them in the 1950s.
There is also some confusion about what the numbers in the rifle names stand for. The model number is not correlated with the size of the caliber, but rather the order in which the models were introduced by Armalite. The 10 stands for the model number of the rifle when it was first introduced by Armalite in 1956. Other model numbers of Armalite rifles include the AR-1, AR-7, and of course the ultra-popular AR-15.
Weight and Length
To the untrained eye, the AR-10 and AR-15 look almost identical at first glance. They have the same visual profile, use the same direct impingement gas system to cycle the bolt, use the same rotating bolt design, and have a similar pool of aftermarket parts and accessories to customize the rifle with.
But once you get some hands-on time with them, the differences become immediately clear. In their most common configurations, an AR-10 rifle has an overall length of about 42 inches and a barrel length of 18 – 20 inches, while a typical AR-15 carbine will have an overall length of 39 inches and a 16 inch barrel.
The AR-10 is also noticeably heftier, weighing in at around 7 – 8 pounds unloaded, compared to 6 – 7.5 pounds for the AR-15. When handling the AR10 you'll notice that the parts such as the bolt carrier group, upper receiver, and lower receiver are similar, but just extended to accommodate the larger rounds.
Very few of the parts are interchangeable between an AR15 and AR10. The interchangeable parts include: the pistol grip, fire control group, stock and buffer tube, and safety.
Because AR-10s were not adopted by the military when they were first created in 1956, the design was not standardized like mil-spec AR15s and has has mostly spilt into 2 commercial varients (DPMS/LR 308 and Armalite AR10). This makes mixing and matching uppers, lowers, and parts between various manufacturers more difficult for AR-10s than AR15s. More on that later...
There’s no getting around it – an AR-10 is going to put a bigger dent in your wallet than an AR-15. The AR-15 is simply one of the most popular and widely produced rifles in history, and that amount of competition has kept prices affordable in both the new and used markets. While the AR-10 was actually developed first, it has only recently seen an explosion in popularity that manufacturers are still struggling to catch up with.
Ammunition cost is another factor – while ammo prices have fluctuated wildly in the past few years, AR-10 owners can usually expect to pay roughly twice as much per round for 308 or 6.5 Creedmoor compared to shooting an AR-15 chambered in 5.56 or 223. [Check out our infographic to see the cheapest ammo prices by caliber in 2022.]
Another major difference between the AR-10 and AR-15 is the size and capacity of the magazine. For the AR-15, there is an almost endless variety of both metal and polymer magazines to choose from, with a 30-round capacity being standard for both military and civilian use (except in states with capacity limits).
Because the AR-10 uses a larger round, magazine capacity is typically smaller, with 10, 20, or 25-roundoptions being the commonly used. Keep in mind that 25 rounds of .308 is quite a bit heavier than 30 rounds of .223, especially since the magazine walls are a bit thicker – for that reason, many hunters and benchrest shooters prefer 10-round AR10 magazines.
Stopping power is where the major difference between these two platforms comes into play. The AR-10 is chambered in .308 Winchester / 7.62x51mm NATO, and most factory loads will clock in at about 2,800 foot-pounds of muzzle energy. Meanwhile, the standard AR-15 is chambered in .223 Remington / 5.56x45mm NATO, which, while boasting a slightly higher muzzle velocity, comes in at roughly 1300 foot-pounds of muzzle energy.
Put simply, the AR-10 packs a much bigger punch, and the combination of a heavier bullet and a flatter trajectory also translates into a longer effective range. While the AR-15 will top out at around 300-500 yards in the hands of the average shooter, the AR-10 can reach out to 600 yards with ease, and most shooters will be able to take accurate shots at excess of 700 yards with the aid of a quality optic.
[As Guy J. Saji states in our upcoming blog about 308 vs 5.56, "Federal’s American Eagle line—staying with a single manufacturer to avoid the varying barrel lengths different brands sometimes use in testing—demonstrates the difference.
Its 55-grain 5.56 NATO load generates 1,223 ft.-lbs. of energy at the muzzle, but the figure drops to a paltry 277 at 500 yards. Conversely, the company’s .308 Win. load with 150-grain bullet launches with 2,648 ft.-lbs. and at 500 yards still delivers 1,089 on target.
That’s almost four times the stopping power at five football field lengths." That's a huge difference, and the ballistic advantages of AR10 calibers like 308 and 6.5 creedmoor are a huge reason why they are so popular with hunters and distance shooters.]
There's no way around it, 308 AR-10 style rifles fire heavier bullets with more powder than AR-15s chambered in 5.56/223. While the heavier buffers of an AR10 do make them easier to shoot than bolt action rifles chambered in .308; you will experience more felt recoil than a soft shooting 5.56 AR rifle, possibly increasing the time needed to get back on target for follow up shots.
If you're used to shooting in the AR platform, however, the extra recoil shouldn't be enough to scare you away from all the advantages that 308 and 6.5 Creedmoor offer. [Check out our blog about 6.5 Creedmoor vs 308 to compare and contrast the calibers.]
Given the significantly higher kinetic energy of the .308 round, it’s probably no surprise that the AR-10 makes for a better all-purpose hunting rifle. In fact, it’s in the running for the best North American hunting cartridge period – Colonel Jeff Cooper, who first conceptualized the modern scout rifle, specifically chose .308 Winchester for his purpose, citing its ability to take any game weighing up to 1,000 pounds. Indeed, the AR-10 is consistently capable of bagging any game in North America short of a grizzly bear – and even that is possible with hand-loaded ammo and skilled shot placement.
The AR-15 also has it’s place as a hunting rifle, and each year innumerable varmints, deer, and wild pigs are taken with this platform. However, some hunters have raised ethical concerns about hunting larger game with the .223 cartridge, and many jurisdictions have placed a .24 caliber minimum for big game in response.
To address this issue, there has been an influx of larger rounds created specifically for hunting out of an AR15 platform including 6.5 Grendel, 300 Blackout, 350 legend, and 450 Bushmaster. To change your AR15 to another caliber all you have to do is buy a complete upper and drop it on your mil-spec lower, although we always recommend tuning the lower to whatever caliber you are shooting.
Interchangeable Parts: Mil-Spec vs. Commercial
Both the AR-10 and AR-15 have two common configurations, commonly referred to as mil-spec or commercial spec. And while mil-spec is built to the specifications of the US military, rifles and aftermarket parts built to these standards are also available to civilians.
For the AR-15, the primary difference comes down to the diameter and threading of the buffer tube – in practical terms, this just means that you can’t fit a mil-spec buffer tube to a commercial lower, and vice versa. The other potential consideration is the quality of the materials – mil-spec is quite specific about tolerances for equipment that peoples’ lives will depend on, while standards for commercial parts aren’t quite as well-defined.
This isn’t an issue if you’re buying from a quality manufacturer with a strong reputation, but it’s something to consider when putting together a budget build. There is also more aftermarket support and availability for mil-spec parts, which makes it the go-to choice for most AR-15 owners. [All our AR-15 rifles, uppers, lowers, and parts are built to mil-spec here at Bear Creek Arsenal.]
When it comes to the AR-10, things are a little more complicated. First, it’s worth noting that there isn’t actually a true “mil-spec” for this platform, since it was never widely adopted or given an official specification by the military. And unlike the AR-15, there was never a push towards industry standardization for AR-10 design.
While this originally boiled down to a choice between the classic Armalite pattern or the first generation LR-308 pattern developed by DPMS Panther Arms, the budding popularity of the AR-10 platform in recent years has resulted in many other manufacturers entering the market with their own patterns, many of which are incompatible with each other.
As it currently stands, the second generation of the DPMS LR-308 is widely regarded as the industry standard for AR-10 builds. While Armalite also offers the AR-10 in a pre-ban configuration that is compatible with a broader range of magazines, including the ones produced by DPMS and Magpul, there is simply more aftermarket support for the DPMS pattern at this time. Still, the AR-10 market is experiencing rapid growth, and this could very well change in the future.
Ultimately, the choice between an AR-10 and an AR-15 comes down to what you need out of your rifle. If you are primarily interested in hunting – especially North American big game – then the impressive stopping power, flatter trajectory, and lower deflection offered by the AR-10 make it a clear winner.
But if you’re primarily interested in recreational or competitive shooting, home defense, or tactical applications where the sheer power of the .308 Winchester round in unnecessary – or if you’re just on a tighter budget – then the AR-15’s superior maneuverability, softer recoil, and faster follow-ups give it the edge.
[We hope this article gave you a clear understanding of the differences between AR-10 and AR-15 rifles so you can decide which one best suites your needs. If you enjoyed the article leave a comment bellow about your experiences with either ArmaLite rifle and check out our other articles such as The Complete Guide to 300 Blackout and Brass vs. Steel Ammo! Huge thanks to Eric Shattuck for his hard work on this article.]