5.56x45mm NATO and .308 Winchester are two of the most commonly used cartridges in the United States.
New shooters, and those looking to expand their collection, may be thinking to themselves:
Is 5.56 or .308 better?
I am well experienced with these two cartridges in both professional and personal contexts. Plus, I’ve taught more than a few people how to shoot.
5.56 is the better choice for most American shooters because it’s lighter, has gentler recoil, is less expensive, and is better for home defense. However, if your plans include hunting large game or shooting past 400 yards, .308 is the round for you.
Read on. I’ll explain my reasons.
What’s the Difference Between 5.56 and .308?
There are a lot of different bullets types and calibers out there and the firearm industry has this annoying tendency to use both Imperial and metric measurements when naming cartridges. So, while “5.56” and “.308” don’t sound equivalent at first, comparing the two is not as much an apples-and-oranges situation as one may think.
So, What Is 5.56?
5.56x45mm NATO is a rifle round developed from the civilian .223 Remington. It’s loaded to slightly higher specs but is externally identical, which means you can use .223 Rem in a 5.56 rifle.
The bullet is .224 inches wide and typically weighs from 55 to 69 grains, though heavier 77 gr and lighter 36 gr bullets are available. Average velocities are about 2,700 to 3,200 feet per second.
5.56 is what’s called an intermediate round. This means that it’s weaker than a full-power cartridge but is still more powerful than a pistol round.
In practical use, this means that the 5.56 cartridge is more of a varmint load than a hunting load. It’s good for coyotes but deer are a stretch.
I’ve hunted Sitka black-tailed deer in Southeast Alaska with a heavy-for-caliber 75 gr hunting load but wouldn’t hunt large corn-fed Kansas deer with 5.56.
However, the bullet’s light-and-fast qualities makes 5.56 an excellent choice for home defense.
That’s because, with the right bullets, 5.56 can penetrate fewer interior walls than pistols or shotguns! All while being effective against home invaders with murderous intent.
A bit of resistance causes the bullet to deflect, bleeding energy.
And How About .308?
.308 Winchester is closely related to 7.62x51mm NATO, though there are some important differences.
.308 is also different from 5.56 in some important ways.
Notably, .308 is a full-powered round, like those used by infantry during WWII.
.308 Win throws .308 caliber bullets at about the same velocity as 5.56, except these bullets range in weight from 120 grains to 180 grains!
This means .308 is capable of more than twice as much kinetic energy compared with 5.56, from an average of 1,300 joules to an average of 3,500 joules.
So, .308 hits harder, which means you can hunt much larger animals with a .308 rifle.
However, your shoulder also experiences that much more recoil.
Also, the components are more expensive. Heavier bullets require more lead, you need more powder to attain those velocities, and the case is longer and wider and requires more brass.
And, if you’re hiking with these guns, each cartridge is noticeably heavier. Your average .308 round weighs 24 grams, as opposed to the 11-gram 5.56 cartridge (source).
Those heavier bullets do maintain momentum and buck the wind better, though. This means that even if your .308 rifle and 5.56 rifle both have the same muzzle velocity, .308 will stay effective far longer.
When Is .308 the Better Choice?
.308 is superior to 5.56 in several different circumstances including:
- When hunting large game
- When shooting at long range
There’s an often-banded-about recommendation to stick to 1,000 ft-lbs of kinetic energy or more to kill a whitetail deer.
Hornady .308 hunting loads (165 gr InterLock SP American Whitetail) will retain that much energy past 500 yards but their 5.56 (55gr GMX Superperformance) might not make it past 100 yards!
Now, bullet construction is more important for ethical kills on deer than raw energy. I wouldn’t hesitate to take a deer at 100 yards with that Hornady 5.56 load, but it still illustrates the difference in power.
Also, that .308 bullet will stay supersonic to 1,025 yards while the 5.56 one will drop to subsonic around 750 yards.
I wouldn’t hunt at that extreme a range with either load, though. That’s when I’ll grab a 6.5 caliber cartridge!
Those heavier bullets will also penetrate more deeply into tough materials.
Take a look at a more detailed comparison of an AR-15 and an AR-10 in .308 in our hands-on review of the PSA PA10.
Related: What Game Can You Hunt With a .308 Rifle? (List of Animals)
.308 Rifle Recommendations
My favorite .308 rifle is my Century Arms C308, but that’s because I prefer rifles with character and have a .260 Remington rifle for the type of hunting I’d otherwise do with .308. It’s more of a fun gun.
For newer shooters, I would recommend a bolt-action .308 such as the Savage Model 110. It’s inexpensive and accurate.
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If you’re looking for a bit more capability, though, then an AR-10 is an excellent choice. AR-10s can be home built like an AR-15, but brands such as Daniel Defense make high-quality .308s.
You can read more about these options in our article on the Best .308 Rifles!
When Does 5.56 Make the Most Sense?
On the other hand, 5.56 is a better choice for the majority of shooting situations the average citizen gets up to.
Training? You want something that doesn’t recoil much but is still accurate. 5.56 wins.
Recreational shooting? You don’t need big, heavy bullets to poke holes in paper. 5.56 wins.
High-volume shooting? Yeah, 5.56 is cheaper than .308.
Home defense? .308 penetrates drywall and exterior walls too much to be considered a safe home defense option except for when you’re in the only house for miles around.
Small and medium game hunting? 5.56 is good for varmints, coyotes, and boar.
Medium-range shooting? Even 7.62×39 can be taken past 350 yards without a problem if you do everything right. 5.56 is good enough to max out shootable distances available at most shooting ranges.
5.56 Rifle Recommendations
For 5.56 NATO, I’d recommend an AR-15.
I’ve built all of mine but there are some excellent production models out there. The Smith & Wesson M&P 15 Sport II is an excellent and economical choice for newer shooters.
If you feel like going against the crowd then the Mossberg MVP Patrol is another great bolt action rifle that’s available in 5.56.
If You Can Get Only One Rifle, Should It Be a .308 or a 5.56 Gun?
Here’s the tough question, isn’t it?
I’m not a one-rifle type of person. My gun safe overfloweth, ’cause I keep buying and building more guns!
However, if I had to grab one gun and leave the rest behind, and my choices were between my .308 rifle and my 5.56 rifle, I’d grab my 5.56 AR-15.
That is, unless I was taking the gun on a hunting trip to harvest game larger than a small deer. Then I’d grab my .308 caliber rifle.
I’ve actually been in this circumstance before and, yes, I did grab my 5.56 rifle. I spent two years without touching any of my other guns!
(Nowadays, though, I’d grab my 6.5 Grendel rifle, but don’t tell my other guns!)
Both 5.56 NATO and .308 Winchester are well-designed cartridges, versatile and worthy of being in any gun collection. And they are available everywhere (provided you can find ammo in stock!).
However, .308 rifles are more powerful than 5.56 rifles, full stop. If you are a hunter and need this power then .308 Win is the cartridge for you.
On the other hand, if that extra powder would do nothing more than beat up your shoulder, then 5.56 is the superior choice. The lighter cartridge is both more comfortable and more economical. And that’s what’s important for most new gun owners today.
Related: Pros and Cons of .308 Rifles: Great Gun, But Not For Everyone