There is an endless supply of debates in the firearms world, from calibers to guns to optics.
While there will always be the classics like .40 S&W Vs. 9mm, there are also some curveballs that are at least easier to settle objectively.
Thankfully, 300 Blackout Vs. .308 Winchester is just one such question!
Apples and Oranges
At first glance 300 Blackout and .308 Win might feel like a good comparison, they are both .30 caliber and they both are shot from an AR.
But really these are so different that they really can’t be considered for the same roles. Kind of.
To break it down real simple like, 300 BLK is generally a 115- to 125-grain bullet pushed at around 2,200-2,300 feet per second.
.308 Winchester is generally a 150- to 170-grain bullet moving at 2,700 to 2,800 feet per second.
At the muzzle, this is a difference of 1,250-foot-pounds of energy. That’s a lot. For a contextual reminder, .44 Magnum at the muzzle is about 1,260 ft-lbf.
.308 Win while not as popular for long range as it once was is still a perfectly capable 1,000-yard cartridge, while 300 BLK is more like a 300-yard shooter.
300 BLK is a great option for home defense, .308 is a horrible option for CQB due to over-penetration, concussion, and size.
And that’s before we get into the part about 300 BLK being designed for an AR-15 and .308 Win needing an AR-10.
Basically -- while both are great cartridges, they are very different. Picking the right one for you is much easier once you agree that they have radically different applications.
Pros of an AR-10 and .308 Win
.308 is a classic round, used by the US military and NATO for decades; this is one of the great American cartridges. It might be getting a bit long in the tooth, but it’s still a reliable workhorse of a round.
Common in bolt-action rifles for hunting, long range precision shooting, and tactical rifle competitions, the most common semi-auto option is with the AR-10.
While the design and development of the AR-10 is a cool story, that’ll have to wait for now. Bottom line -- AR-10s are great rifles these days and I highly recommend getting one.
If you’re worried about multiple long range bad guys coming for your chicken tenders or want to turn big bucks into freezer fill from hundreds of yards away, the AR-10 in .308 Win is there for you.
Pros of an AR-15 and 300 Blackout
For a full break-down on why 300 BLK is awesome, take a look at our Complete .300 Blackout Guide, for now though let’s take a look at the short version.
Take a standard 5.56 AR-15 and give it a 300 Blackout barrel, BAM -- you have a 300 Blackout rifle now. Being easy to convert and using almost exactly the same parts as a normal AR-15 makes 300 BLK really easy to get into.
It also makes spare parts a lot easier.
Ballistically, 300 BLK is basically the same as 7.62x39. So if you want AK power in an AR-15 format, here it is. This means a hard-hitting but short range cartridge that lives to be suppressed.
Boar, deer, or things that go bump in the night within 250-300 yards is the bread and butter of 300 BLK.
For home defense, this is an outstanding round with lots of stopping power but minimal over-penetration of home walls.
If you want to know more about the differences between the AR-15 and the AR-10, we got you covered with our article AR-10 vs AR-15!
What About Bolt Rifles?
While .308 bolt rifles are a dime a dozen and are far more common than AR-10s, finding a 300 BLK bolt rifle is a bit harder -- but not impossible at all.
Personally, unless you’re restricted due to state law about using a semi-auto rifle while hunting -- I don’t see a lot of pros for a 300 Blackout bolt rifle.
It’s lighter weight than an AR-15, but not by a lot. If you want to get as quiet as possible though, a bolt action rifle with a suppressor is about as good as it gets for deer and boar.
For .308 Win the world is available to you in bolt rifles. Precision long range rifles, hunting rifles, super lightweight mountain rifles, F-class competition rifles -- basically every type of rifle made today is available in .308 Winchester if you want it.
This is where, oddly, the .308 Win and 300 BLK actually get a lot closer to each other. Since being subsonic requires that both cartridges are moving at about the same speed, the ballistics of each get a lot closer.
300 Blackout subsonic and .308 subsonic ammo are also basically the same grains, or at least they are available in basically the same.
So… when it comes to subsonic, there isn’t a big difference.
Except that 300 BLK is really designed for it and .308 Win really isn’t. While .308 Win can do it, finding ammo for it is a lot harder. You’re going to pay more and you’re getting the exact same performance as you would from 300 Blackout.
If your plan is to shoot quietly and use subs, I would strongly recommend getting 300 BLK. It’s just easier.
Choosing between these two cartridges should be fairly clear based on what you want to use them for.
If your focus is on short range, stopping power, in a compact form -- 300 Blackout is the clear winner.
If you need to reach out and touch something far away and you want to make sure it stays down when you do, .308 Win won’t do you wrong.
[We'd like to extend a huge thank you to David Lane for his work in thoroughly covering this topic. Check out other helpful articles like 6.5 Grendel vs 6.5 Creedmoor and 308 vs 5.56 and leave a comment about what you liked!]