The AR-10 platform has exploded in popularity within the past decade as more and more people seek a semi-auto rifle with improved range, hitting power, and accuracy.
If you’ve found yourself looking to jump onto the AR-10 train, you’ll quickly realize that this platform has an almost paralyzing number of calibers to choose from.
So, which do you choose? How do you know what the best AR-10 calibers are?
The Quick List
- .243 Winchester
- .260 Remington
- .308 Winchester
- 7.62x51mm NATO
- .338 Federal
- 6.5mm Creedmoor
Table of Contents
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What’s the Difference Between an AR-15 and an AR-10?
Before we determine the best AR-10 calibers, it’s best to start by answering the AR-15 vs. AR-10 question.
The company Armalite was birthed in the 50s, shortly afterward pitching their AR-10 rifle (chambered in 7.62x51mm) to the U.S. Army for adoption.
The Army decided they wanted a smaller round and lighter gun; thus, the AR-15 became the most popular battle rifle in American homes today rather than the AR-10.
Visually, the rifles look the same, but the food is different here. AR-15s shoot the iconic 5.56mm round, while AR-10s are now typically chambered for the much larger .308 Winchester.
It’s a result of being designed for larger rounds that the AR-10 can shoot further, more accurately, and with more impact than an AR-15.
8 Best AR-10 Calibers
.243 Winchester
A very popular cartridge, you’ll typically have little problem finding .243 Winchester on gun store shelves.
Though it’s not as good as .308 Winchester for long-range accuracy or hitting power, it serves as a very nice cartridge for the light-framed shooter looking for something with a bit more oomph behind it than an AR-15.
The reason for this is the decreased recoil. You can shoot an AR-10 chambered in .243 Winchester without feeling as if a mule has repeatedly kicked you by the end of the day. It makes for a darn good deer cartridge as well.
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Perchance your locale bans hunting with .22 caliber bullets, an AR-10 chambered in .243 Winchester can make a very nice alternative to a traditional AR-15.
Just know that if you were willing to step it up to .308 Winchester, you’d end up with less wind drift and further reach.
.260 Remington
You’ll notice that a lot of AR-10 cartridges are just different flavors of the .308 Winchester. The .260 Remington is one of those, being a .308 Winchester necked down for a .264 bullet.
You’ll still get excellent long-range ballistics with these cartridges (in many cases better than .308 Winchester), but with the added benefit of reduced recoil compared to a .308 Winchester as well.
A .308 Winchester really isn’t that bad, to begin with, but if you’re talking about hour after hour spent at the range or a lighter-framed individual, every decrease in recoil helps.
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You have to be careful with over-penetration with these cartridges, though, so keep that in mind if you’re thinking of using these for self-defense purposes.
.308 Winchester
Ahhh, the classics.
This is easily the most common caliber you’ll find an AR-10 chambered in and is a classic for a reason: it rocks. For proof of such, just look at how prevalent this cartridge is.
It’s likely to be one of the most popular hunting cartridges in the world simply because it does fantastic for such a large gamut of issues.
Snipers use it, hunters use it, and you can even find the occasional PRS shooter using it as well. With a .308 Winchester, you can easily harvest deer, wild hogs, elk, and black bears.
I’ve heard reports of other guys using this caliber on the bigger bears with success, but I’d personally want a .30-06 Springfield for things that could easily eat me.
It’s hard to go wrong with a .308 Winchester.
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7.62x51mm NATO
This is what the original AR-10 was chambered in. If you ask around, you’ll find that a lot of guys shoot these out of their AR-10s chambered in .308 Winchester.
If you try to shoot a .308 Winchester in a barrel chambered for 7.62x51mm NATO, you could soon end up with fewer fingers on one hand.
7.62x51mm NATO ammo is plentiful and shoots with similar ballistics to a .308 Winchester round. This, in turn, means the 7.62x51mm NATO can serve as a fantastic hunting cartridge for even many larger animals.
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.338 Federal
This is a .308 Winchester which has been necked up to accept a .338 bullet. There are pros and cons to this. For starters, you will end up with a bigger bullet hitting your target. A lot of guys out there like using this for bears, moose, caribou, and elk as a result.
It can still easily handle hogs and deer as well, though, if that’s more up your aisle. That bigger bullet comes at a cost, however. Compared with the .308 Winchester, you will see diminished range and more bullet drop.
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So, no, this isn’t the best long-range cartridge, but if you want your AR-10 to hammer away at things within 300 yards with a bigger bullet, these can serve the trick.
6.5 Grendel
It seems as if, right now, any cartridge with a 6 in front of it is common at PRS events, with the 6.5 Grendel being no exception. It’s still not as powerful or accurate of a round as the .308 Winchester (particularly when wind is involved).
Still, it does have one bonus a lot of shooters will be interested in: about 2-3x less recoil than a .308 Winchester.
If you’re looking at a situation where you’re dumping mags and need accurate fire (think hog hunting), lower recoil can drastically improve your shot placement.
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Should you be more interested in large game, though, you’ll want to find something bigger.
6.5mm Creedmoor
Another cartridge that’s really gained steam within the PRS world, the 6.5mm Creedmoor serves as a fantastic chambering of the AR-10. And why has it performed so well in PRS? Because the long-range accuracy you can get with a 6.5mm Creedmoor is superb.
In many cases, it’s better than .308 Winchester.
While it doesn’t have the kinetic energy that .308 Winchester does, it still stays supersonic out to roughly 1100 yards and can serve as a very potent deer harvester. And all this with reduced recoil. If you’re pouring lead down range rapid fire, your follow-up shots will take time to line up.
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For more info on the 6.5mm Creedmoor, check out our in-depth guide HERE.
7mm-08 Remington
This is a .308 Winchester case necked down for a 7mm bullet, and – if you can find one – serves as an awesome AR-10.
Most of what I see out there are typically bolt-action rifles in 7mm-08 Remington, but if you can find an AR-10, you’ll end up with a rifle with a very flat trajectory, a high degree of accuracy, less recoil, and report than a .308 Winchester, and that can handle a heck of a lot.
Deer, black bear, moose, elk can all be handled by a 7mm-08 Remington chambered AR-10. Obviously, you would want heavier bullets for the bigger stuff (around 160gr for moose).
Finding ammo won’t be the difficulty you’ll have here, as this has been around for quite some time. It’s finding the rifle which will prove to be a challenge.
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How Do You Choose the Best AR-10 Chambering?
The same way you choose the best tool for any other job: you consider what needs to be accomplished.
There are three main camps you’ll find people falling into when they’re looking at purchasing a weapon: for self-defense, hunting, or competitions.
We could even break hunting down into big-game hunters and medium-sized game hunters here.
Out of all these, what do I think is the best? Here’s my take…
Self-Defense
I’d stick with the classics here, and that’s why I would choose .308 Winchester if my sole intention in buying an AR-10 was self-defense. My main reasons for this are due to how easy it is to get this ammunition compared to a lot of these other cartridges.
I can find .308 Winchester pretty much every time I walk into a gun store around here, and the sticker price won’t make me gag.
In a fight, you fall back onto your level of training, and the easier/cheaper you can find ammo, the easier/cheaper it is to train. More training opportunities make for a better self-defense gun for me.
Sure, some supercharged, exotic round may sound cool, but if you were only ever able to find or afford a minimal amount of ammo, you quickly find yourself with an expensive stick in your hands once you burn through it.
Hunting
Really, I think 7mm-08 Remington is one of your best bets here, regardless of whether you’re hunting the bigger stuff or whitetail deer. It can handle them all.
I like regular .308 Winchester here as well, but I like the idea of something just as tough but with less noise to it.
If I’m at the range, I have all kinds of ear protection. When I’m hunting? Ehh, typically not. I’ll take any advantage I can get when it comes to a lower-decibel round for work out in the woods.
Competition
To me, this is a no-brainer. I’d choose 6.5mm Creedmoor.
Yeah, there are a lot of other cartridges within this 6mm ballpark that are pretty sweet as well. I get that.
But from our list above, 6.5mm Creedmoor is my favorite for dead-on, competition-grade accuracy. There’s a reason this is so popular within the world of PRS – it wins medals.
What Are Some Other AR-10 Calibers Out There?
Still looking for more?
You can find a manufacturer out there willing to make an AR-10 (or an AR-15, for that matter) out of just about any caliber out there.
If we’re looking at AR-10s, these are just a few more possibilities you’ll see on the market besides what we’ve chosen…
- .243 Winchester
- .260 Remington
- .300 SAUM
- .300 Winchester Magnum
- .308 Winchester
- .338 Federal
- .338 Lapua Magnum
- .358 Winchester
- .45-70 Government
- .458 HAM’R
- 6mm Creedmoor
- 6mm ARC
- 6.5mm Creedmoor
- 6.5 Grendel
- 7.62x51mm NATO
- 7.62x39mm
- 7mm-08 Remington
- .30-06
- .500 Auto Max
Final Thoughts
An AR-10 is a fantastic weapon, and I think it’s saying something when you consider that it wasn’t the AR-15 that Eugene Stoner pitched to the Army first – it was the AR-10.
If you’re debating as to whether or not you should delve into the world of AR-10s or not, I would say go ahead and take the plunge (before you can’t).
Are there particular cartridges you prefer over others? What has been your experience? Let us know in the comments below! Looking at buying your own AR-10? Check out our guide on the Best AR-10s.
10 Leave a Reply
A bunch of those cartridges listed at the end are in fact not available in an AR10.
6.5 Grendel and 7.62x39 are both ar-15 rounds…
7.62 x 51 and .308 fit the same chambers and use the same bullet diameter (.308) . Why would fingers get blown off when firing a 7.62x 51 from a .308 Win.? 7.62 NATO is a lower pressure round than a .308 Winchester.
I agree totally, that statement makes no sense. I found this on the Top Brass website. "Bearing in mind that the .308 Winchester is specified for a ‘hotter’ powder load than that of the 7.62, firing it in a chamber with the added headspace will stretch the brass much more than the lower powder load 7.62. With a thinner brass wall design, the results may lead to an over-stretching (i.e. case ruptures, etc.).
In summary, the biggest difference between the .308 Winchester cartridge case and the 7.62 NATO cartridge case is with the chambers they are designed for. Manufactured .308 Winchester and 7.62 NATO rounds can safely and effectively be fired in rifles design for .308 calibers, but manufactured 7.62 rounds should be shot only within rifles designated for 7.62 calibers."
It makes some sense, but I doubt it would be an issue, if you were using new .308 brass and watched your powder loads. I'm not going to lose sleep over it.
That’s not the only comment that doesn’t make sense:
“I like regular .308 Winchester here as well, but I like the idea of something just as tough but with less noise to it.” In reference to 7-08, really…can he hear the difference?
The 260 isn’t mentioned, even though it’s a better, albeit slightly, round than the Creedmoor. There’s not 10c difference in most of what he hyper-analyzed.
Read it again.....it says shooting a 308 in a 7.62 NATO barrel is a problem.....and use a 7.62 NATO in your 308 for reduced recoil and sound
It is not the ammo, but to the barrel. So, if the barrel is designed for 7.62x51, you can fire .308 however the pressure of the .308 might be a little much for it. Just like the .223/.556, so they built the .223-Wylde. The .223-Wylde refers to the barrel and not to the ammo, so it allows .223 and .556 to be fired from that barrel safely.
7.62x39 is an AR-15 round as well
6.5 grendel is an ar15 round!
6mm ARC and 6.5 Grendel are made for the AR-15 platform not AR-10. Otherwise, good info to help those that may want to into the AR-10 shooting platform.