If you want to go big, if you want something that packs a real punch, if you want to never financially recover after your friend mag dumps your rifle -- then .458 SOCOM or .50 Beowulf just might be for you!
Two of the biggest cartridges you can fit into the AR-15 rifle, .458 SOCOM and .50 Beowulf are big bad rounds that move slowly and carry a lot of energy.
While there are a LOT of similarities between the two, the right one for you can be tuff to figure out. We’ll take a look at where they came from, why they’re here, and what they can do for you!
I love talking about the .50 Beowulf cartridge because I get to talk about the 1,000-year-old Epic . Yes, the old English poem from that one English Lit class you slept through ?? years ago.
Beowulf (the hero) was a monster-slaying badass who saved his mead hall and became king. Beowulf (the cartridge) is a meat harvesting thunker of a cartridge that can absolutely protect your halls from anything that goes bump in the night.
Invented by Bill Alexander of Alexander Arms, the .50 Beowulf is basically the answer to the question of just how big of a cartridge can we fit in the AR-15. Why? Because we can. Literally.
As awesome as 5.56 NATO is, there is a simple fact that there is only so much energy that can be wrung out of a 55gr-72gr projectile. If you want something to truly smash at short range, you need to raise the grain count.
.50 Beowulf does that by slinging 200gr-420gr rounds at the target.
Fun bonus fact -- the monster that Beowulf (the hero) slays in the poem to save his mead hall is Grendel. Bill Alexander is also the man behind the 6.5 Grendel cartridge.
.458 SOCOM has an even cooler origin story, assuming it’s true.
Something that Black Hawk Down doesn’t cover in the movie was that many Somalis at the time would chew Khat, a plant native to the area.
Ingesting Khat reportedly causes excitement, loss of appetite, and increased pain tolerance. Much like the Moros that resulted in the creation of the .45 ACP, the Somalis were able to shrug off hits that should have neutralized the threat.
Years after the battle, SOCOM members informally spoke with a number of people about the issue. Marty ter Weeme of Teppu Jutsu, LLC and Tony Rumore at Tromix took up the case and in 2000 invented the .458 SOCOM cartridge.
Much like the .300 Blackout, .458 SOCOM is designed to use as much of the standard M4 as possible. But while .300 Blackout had the added requirement of not reducing magazine capacity, 458 SOCOM forgoes capacity in favor of sheer size.
Due to the ease of conversion and some… other factors that we’ll touch on in a moment, .458 SOCOM quickly gained a following in the civilian world for hunting and home defense.
While I’ve read and heard reports that .458 SOCOM was used by some US special forces units for mission-specific roles, it was never adopted nor used widely by any military.
Copyright and Names
Something kind of odd that I need to mention is that .50 Beowulf is a copyrighted name held by Alexander Arms.
While some would consider this poor form, AA is very strict about the use of .50 Beowulf when it comes to other brands using it. Like calling their uppers .50 Beowulf or their ammo .50 Beowulf, etc.
To get around this speedbump, the firearms industry quickly decided that instead of calling things .50 Beowulf they would instead use the cartridge dimensions as a name -- 12.7x42.
Bear Creek Arsenal and most manufacturers will normally call their uppers, barrels, bolts, and more 12.7x42. This is the same thing as .50 Beowulf, except the name.
For some context keep in mind that M855A1 is a 62-grain round moving at around 3,000 feet-per-second with about 1,239 ft.lbf of energy at the muzzle, 1,000 ft.lbf at 100 yards, and 625 ft.lbf at 300 yards.
Weight for weight, round for round, .458 SOCOM, and .50 Beowulf really don’t have much difference ballistically. Anything one round can do, the other can too.
In fact, outside of the first 100-yards, the differences are effective entirely negligible.
At the muzzle, a 350gr XTP .50 Beowulf will have about 2,440 ft.lbf of energy.
.458 SOCOM with a 350gr FMJ round will have 2,116 ft.lbf of energy.
Now sure, that is 320ish more foot-pounds. But in the grand scheme of it all… that isn’t much when it’s already putting out over 2,000. Look at it this way, .308 Win At the muzzle is about 2,700 ft.lbf of energy.
9mm is about 350 ft.lbf.
That means .50 Beowulf is about 9mm more power than .458 SOCOM, but .308 Win is also a little under a 9mm of power over .50 Beowulf.
I will absolutely contend that anything .50 Beowulf can do, .458 SOCOM can too.
And another thing -- .50 Beowulf doesn’t stay on top for long. The power drop-off for both cartridges is pretty sharp, but .50 Beowulf drops faster.
After 100 yards the difference drops to only 115 ft.lbf and by 230 yards the tables turn and .458 SOCOM is more powerful due to less loss of velocity.
I know I just threw a lot of numbers at you but the takeaway is this; .458 SOCOM and .50 Beowulf are ballistically similar enough that they can be effectively considered equal.
How Far Is Too Far?
One of the downsides of lobbing chonky bricks for bullets downrange is that they drop like rainbows. These are big rounds with a lot of surface area and many have flat noses, horrible for ballistic coefficient.
If you adhere to the maxim of needing 1,000 ft.lbf for deer-like game, then both .458 SOCOM and .50 Beowulf are roughly 250-yard cartridges. Depending on the exact type of ammo you’ll get between 240-270 yards and still have at least 1,000 ft.lbf.
However, even at that range, you’ll be getting 33 inches of drop -- or 12+ MOA/3.5+ MILs using a standard 100-yard zero.
Shots like that are entirely doable, but it’s something to keep in mind.
If you want something more point-and-shoot, you’ll be limited to around 200 yards and
you’ll need to play around with your zero.
Double-check the math and your personal rifle, but generally speaking, a 175-yard zero will give you a +/-4” of rise/drop out to 200 yards.
Little tricks like this can help a lot in extending your practical ranges with these big beefy calibers.
If you are really into shooting a rifle like a howitzer, you can push some loads to about 350-yards. You’ll still have about 800 ft.lbf of energy, but aim high because it’s 50+ inches of drop by then.
Now that we agree that .458 SOCOM and .50 Beowulf can do the same thing, what exactly can they do?
At the moment I’m writing this, the cheapest factory ammo for either cartridge is $2 a round or more. So unless you really enjoy blowing rent money at the range, neither of these are great for range time fun shooting.
Sure -- they are great for a once-in-a-while blast, but you won’t be going every weekend for a case or two of shooting.
Really where they shine is hunting… and they’re usable in home defense.
When they first came on the market, they were some of the only subsonic options out there for the AR-15.
And while both calibers come in expanding bullet options that make them great soft tissue rounds. But they also both have a problem of over-penetration in things like drywall. Or brick. Or really basically anything you might find in your home.
Subsonic loads can reduce the problem of shooting through your house, the neighbor’s house, and the 5 houses behind that -- but there are still much better calibers for that application.
If you want a close-range punch in home defense, I would strongly recommend 300 BLK over either .458 SOCOM or .50 Beowulf.
Now, this is where these calibers really come into their own.
5.56 NATO can do a lot of things, but hunting with it is always a little iffy. Varmits fear it, but larger critters do not. Sometimes, it can be downright unethical to even try 5.56 NATO on a beast.
.458 SOCOM and .50 Beowulf gives you a LOT more punch per round and are more than capable of taking some major animals.
Personally, neither would be my first pick for Elk or bigger -- but at close enough range it can work nicely.
Anything smaller and both cartridges perform outstandingly well.
Make smart shots from 200 yards or less and you have an awesome fridge filler.
Reducing Your Costs, Availability, and More
The huge downside to both calibers is just how freaking expensive they are to shoot. Plinking ammo is $2 per trigger pull and good hunting ammo can run another 50 cents or more on top of that.
For low-volume shooting, factory ammo might be best. And it’s surprisingly available too.
f you want to stack them deep though, you might want to look into reloading. Brass and components are fairly easy to get, but working up a load can be tricky. Take your time and do it well before hunting!
Something else worth touching on is magazines.
One of the major strengths .458 SOCOM has over .50 Beowulf is that it was designed to work with as many standard AR-15 parts as possible and that includes magazines.
Standard mags work just fine for .458 SOCOM. You can get new followers that help a little, but they aren’t required at all.
50 Beowulf though… you really need new mags. They can work with standard magazines, but it’s not recommended.
Convert My Rifle or Buy A New One?
Normally I’m a big fan of building your own or doing your own conversions, but both of these calibers are ones that I would recommend buying a new upper for instead.
Because of their size, there are extra small steps that really help in reliability, like enlarging the ejection port.
Both are designed to work with standard lowers with no changes [although a heavier buffer can really help out with recoil], so all you really need is a new complete upper.
If you do want to build your own, you’ll need a barrel, a bolt or bolt carrier group, and a different upper receiver that is designed for large cartridges.
.458 SOCOM uses .458 SOCOM bolts, they are basically .308 Win bolts that fit in AR-15 carriers.
.50 Beowulf uses .50 Beowulf bolts. They are kind of like 6.5 Grendel or 7.62x39 bolts, but slightly different sometimes.
If you can get it a matched bolt and barrel is a big help, but if not -- use what your barrel manufacturer recommends and preferably buy from the same source just to make it easier.
As I mentioned, for .50 Beowulf you’ll need new magazines. But for .458 SOCOM you can use standard GI mags.
What Is Better: .50 Beowulf or .458 SOCOM?
Ballistically, they are basically the same.
Impact on your wallet, they will do about the same damage.
Finding them on the shelf at your local ammo store, roughly the same odds.
Really -- when you break it down… there just isn’t much difference between the two.
If I had to choose one over the other, I would choose .458 SOCOM.
It’s not that .458 SOCOM is better than .50 Beowulf, it’s that there are some oddities about .50 Beowulf that are just a little annoying.
The magazines are a big one, but .50 Beowulf is also just a little less reliable to feed and extract and tends to break components just a little more often.
You won’t be going wrong with either caliber and as we’ve seen, they really are basically the same. But personally, I like .458 SOCOM slightly more.
And there you have it, everything you need to know about the two big ones.
Although they’ve grown outdated for home defense, .50 Beowulf and .458 SOCOM are still very capable hunting cartridges and they are just really fun to shoot.
They pack a punch and kick like a mule, but when nothing else will do -- go big or go home.
[We would like to extend a huge thank you to David Lane for his hard work on this article! For more information on big bore AR-15 calibers check out our Guide to 450 Bushmaster or switch it up a bit and find everything you need to know about AR-15 pistols!]