Choosing .308 Ammo: What you Need to Know
The venerable .308 Winchester (7.62x51mm NATO) cartridge has been used for decades by everyone from casual plinkers at the range, to Special Forces units around the world, and during that time it has served admirably in every capacity imaginable.
Now however, there are many who would tell you that the legendary .308 is a fading star, soon to be replaced by relative newcomers that promise better ballistics, more stability at range, or lighter recoil.
Wrong. These modern cartridges have their place to be sure, but it’s going to take more than that to unseat the .308 as the king of the short-action rounds, both for the average shooter, and for the various militaries that have adopted it.
So, since the .308 is here to stay, and is likely to remain cheaper than those other fancy new calibers for quite some time, the question remains: how do we get the best performance out of our .308 rifles?
I’m glad you asked! The answer is fairly simple though... the best ammo.
While “best rifle” can mean lots of things, and probably means something different to each person you ask, “best ammo” is a bit easier to pin down, so let’s start there.
Choosing the perfect load for your .308 rifle can be a bit daunting if you don’t know where to start so let’s start at the beginning.
History of the .308 Winchester Cartridge
In 1952, the Korean War was chugging along, marking the beginning of US involvement in a series of dustups with China and the USSR over the spread of Communism.
At home, the manufacturing juggernaut of the US industrial complex was shifting away from the frantic production of guns and bombs that had dominated the previous decade, and was instead beginning to produce consumer goods such as microwaves and refrigerators.
This was also the year another American Institution was conceived: The Chevy Corvette.
They just don’t make ‘em like they used to.
Of course, not everyone was making home-appliances and sportscars. The US military, for one, saw the vast improvements in warfighting materiel that had been brought about by the Second World War, and wanted to keep that ball rolling.
One area in particular that they wanted to improve was the current US battle rifle, the legendary M1 Garand.
The Garand was big, heavy, accurate, and spit out the devastatingly effective 30-06 cartridge, and was according to some fairly smart people “the greatest battle implement ever devised”.
But, as always, America felt it could do a little better. After all, the Garand was hard to carry ammo for, and a pain to lug through muddy jungles. Not to mention the problems inherent with the 30-06 round itself. Ever tried firing a 30-06 on full auto? Trust us, it’s not an experience you’ll want to repeat.
There were also problems with the rifle’s somewhat limited capacity, and the amount of ammo soldiers could conceivably carry.
Enter the 7.62x51mm NATO round, which sought to address all of these issues. It was smaller and lighter, but offered sufficient down-range energy and less recoil, making it an ideal choice for machine guns like the M60, variants of which are still in service today.
Though it would eventually be phased out in favor of the even lighter 5.56x45mm as the round of choice for America’s main battle rifle, it was also the round of choice for the M14 (the precursor to the M16), which also still sees use, albeit in a modified, distantly-related form as the Mk 14 EBR.
Today, the round is sold by just about everyone who makes ammo, though it was first branded by Winchester as the .308 Winchester.
Note: There are some differences between the .308 Winchester and the 7.62x51mm NATO rounds, but they are relatively minor, and SAAMI Spec says you can use them interchangeably.
Modern .308 Ammo
The .308 Winchester round, like most all commonly produced rounds, has seen a lot of development and improvement over the years, especially in military circles.
Today, it remains the king of the short-action cartridges, and it is used by snipers, Special Forces, and target-shooting enthusiasts the world over.
Choosing .308 Factory Match Ammo
That brings us back to our original question: how do we pick the best .308 ammo?
Well, the very best ammo is always going to be handloaded ammo that you tailor to your specific rifle, shooting style, and needs.
However, you can also get pretty close with Factory Match ammo that you can buy right off the shelf at your local gun store (or more likely order online).
What the Heck is “Match” Ammo, Anyway?
“Match” ammo is a byword for factory-loaded ammo that’s been given a bit of an extra touch to make it more accurate. In some cases, this means the ammo was designed, loaded, and tested all with the intent of making the most accurate ammo possible.
In other cases, it just means the manufacturer identified a production lot of ammo that was more accurate than others. Because there’s no industry standard, it’s important to know what “match” means for your particular manufacturer.
Choosing Ammo for Your Gun
I want to stress again, the best thing you can do for your gun is to load something specifically for it, but that’s not always an option. The next best thing is to select a factory load for your rifle the same way a handloader would work up a round, but with a few key differences.
Special Purpose Rounds
First things first, you have to decide what you’re doing with your ammo. For this article, we’re going to approach things from the perspective of a competitor or target shooter looking to punch the smallest grouping of holes possible in a piece of paper.
That being said, if you’re hunting, you need to look at things like sectional density, tip type, and a host of other things outside the scope of this article. In general, you’ll want to pair your round to the game you’re hunting...a 168gr Core Lokt will lay out a deer, but might have trouble on something like an eland or other large game, for example.
With that out of the way, let’s look at how to pick the best target ammo, and save the hunting considerations for later.
Start with Quality Manufacturers
Step one should be to identify a handful of quality manufacturers to purchase ammo from.
Of course, if you ask ten different people to name the best ammo manufacturer, you’ll get ten different answers, but there are some manufacturers that you’ll hear come up often when folks in the know discuss accurate ammo.
Here are some of the best, in no particular order:
Black Hills (My personal preferred flavor)
Hunting Shack Munitions
American Ballistic Technologies
Each one of these manufacturers has a number of “match-grade” and other hyper-accurate offerings that should be considered a good starting point in your quest for the perfect .308 ammo.
I’d suggest starting with about 5 manufacturers, and getting a box of about 20 rounds from each for your testing.
Make sure you take note of the lot numbers (the number that tells you which batch of ammunition your particular rounds came from) so that you can try and hunt down that same lot again if you choose to buy more.
This will give you the most consistent ammo possible.
Picking the Right Bullet Weight
Many shooters go their whole lives without worrying about bullet weight, and they do perfectly fine. They compete, put meat on the table, and defend themselves with no issues.
That being said, we want the very best ammo for our guns, and we would never dream of settling for “just fine” so we have to take bullet weight into account.
There are two big things to keep in mind when it comes to picking the right bullet weight for your rifle: twist rate and velocity.
Understanding Twist Rate
If you’ve ever shopped for a long gun, you’ve probably seen a “Twist Rate” on the listing along with all the other specs like barrel length and what not. Twist rate refers to the rate of rotation of the rifling grooves inside the barrel.
So, if you see a twist rate of 1:16, you should know that the rifling, and thus the bullet, completes one full rotation every 16 inches. That rotation imparted to the bullet by the rifling is what stabilizes your bullet and gives you an advantage over say, a smooth-bore musket.
Now, ideally you want to find the ideal bullet weight for your gun by matching the twist rate to the right bullet weight. There’s a lot of math that takes in things like velocity and maximum pressures, but in general here’s what you should be using for .308 ammo:
1:15 twist: up to 150 grains
1:14 twist: 150 – 168 grains
1:12 twist: 168 – 170 grains
1:10 twist: 170 – 220 grains
1:8 twist: 220 grains or more
Once you have your manufacturers, and you have your ammo purchased, it’s time to start testing.
The method we’re going to use is a simplified version of the ladder testing method that handloaders use to identify the perfect load for their gun. Basically, its a process of elimination to sort out the most accurate rounds.
Set up targets at 100 yards. Start with a clean rifle (gun grease can help with this), and then fire two fouling shots to get the gun dirty, then run a bore snake through it once. We’ll run the bore snake through the gun after each set of rounds to make sure we’re testing each ammo type under the same (or at least similar) conditions.
Now for the fun part: testing the ammo.
To start with, fire three rounds from your first set of ammo. You’ll want to use a set of sandbags, or a bipod to take as much of the human element out of things as possible. Mark your groupings and see how you did.
Then, run the bore snake through the gun, and do try again with your next manufacturer or flavor of ammo. Me personally, I’ll test about ten loads and then identify the top five, and then test those again.
If I get the same results, I’ll test the top two one last time, and decide from there.
Once You’ve Identified Your Rounds
Once you’ve found the particular flavor of firearm fuel that your gun likes the best, its time to hunt down some more ammo (preferably from the same lot of ammo) and go to town.
Getting into Handloading
If you want even more accuracy and consistency, you’ll want to try your hand (zing) at handloading. Handloading your own ammo does a couple of things.
One, it give you complete and total control over the round, from the case to the bullet itself, which gives you a great deal of freedom to make your ammo just the way you want.
Two, it allows you to load up a much more precisely designed round that will let you squeeze even more accuracy out of your gun.
Because of this, handloading will always, always, always be superior to factory ammo, and if you want to get into precision long range shooting in any real, meaningful sense you’ll want to handload.
You’ll also learn a heck of a lot about ballistics and what your gun likes along the way, so it’s definitely worth looking into if you want to get the most accuracy at the range, or in competition.
Final Thoughts on Factory .308 Ammo
For everyone else though, factory .308 ammo is certainly good enough for hunting, plinking, and less accuracy-focused competitions like 3-Gun.
Start with factory ammo made by a reputable, quality manufacturer, and then test to find out what your particular rifle likes the best. Once you do, get out and enjoy your new ammo. You’ll be glad you did.