Big Bore Goodness: The Big Horn Armory AR500 500 Auto Max Pistol

500 auto max pistol
The Big Horn Armory AR500 500 Auto Max Pistol is about as big a bore as it gets. (Photo credit: Kat Ainsworth Stevens)

Do you like big bores? Want a gun that’s chambered in the biggest caliber possible for the platform? Then you want the Big Horn Armory AR500 500 Auto Max Pistol. This is a big bore gun that’s been downsized—as much as you can downsize such a gun—so it’s compact, accurate, and reliable. This is going to be one of those YMMV reviews, so tell us what you think in the comments.

ar500 auto max pistol
This is basically the ultimate big bore AR pistol. (Photo credit: Kat Ainsworth Stevens)

What’s the BHA AR500 500 Auto Max Pistol?

The Big Horn Armory AR500 500 Auto Max Pistol is, as the name implies, an AR-platform pistol chambered in 500 Auto Max. The 500 Auto Max round was designed by none other than Greg Buchel, president of Big Horn Armory, in 2018. Word is Greg did it because their customer base was so thoroughly geared toward older shooters, they wanted to draw in the next generation of big bore shooters. Enter the 500 Auto Max in an AR-platform that was virtually guaranteed to get some attention.

This pistol is the next iteration of the 500 Auto Max lineup (the first was a rifle which I’ve taken hunting and can report that it makes very big holes). By turning the bigger gun into a smaller, portable pistol, Big Horn Armory makes it easier to have your big bore and take it with you more often.

buffer tube on AR pistol
Yes, the gun has a naked buffer tube. That’s likely how it’ll stay until the dust really settles on the pistol brace legal issues. (Photo credit: Kat Ainsworth Stevens)

Specifications of the AR500 Auto Max Pistol

This pistol ships with a naked buffer tube—no pistol brace. That isn’t surprising given the legal ups and downs surrounding pistol braces. It has a 10-inch barrel with a 1 in 24 twist rate, which is necessary to stabilize the big 500 Auto Max round.

The muzzle is threaded so it’s suppressor-ready if you want to go that route. Or you can attach the muzzle device of your choice. An M-LOK compatible forend facilitates the quick addition of whatever lights, lasers  and other gear you may want, and a full-length Picatinny rail provides plenty of real estate for optics.

Of course, this is a pistol, not a rifle, so you might find a red dot sight is better than a magnified scope.

A match grade RISE Armament Rave 140 trigger is a nice addition to the gun’s specs—you don’t always get nice triggers straight from the factory. The Rave 140 is a single stage trigger with a smooth pull weight of 3.5 pounds, a clean break, and short reset.

The action is made of 7075 aluminum that’s hard anodized for longevity. An integral rear swing swivel mount makes it possible to add a single-point sling. The pistol has an empty weight of 8.1 pounds, which is admittedly bulky for an AR pistol, but it makes sense considering the caliber. Available magazines are 5- or 9-round capacity. Big Horn Armory offers it in any color you want as long as it’s black.

500 auto max engraving
Want an AR pistol with .50-caliber bullets? You’re in luck! (Photo credit: Kat Ainsworth Stevens)

What’s the 500 Auto Max?

The question of what the 500 Auto Max is, is probably the reason you opened this article. The 500 Auto Max round can easily be described as a rimless 500 Smith & Wesson. BHA’s Greg Buchel shared a few thoughts on it:

The .500 S&W Magnum, while a fine revolver cartridge, really comes into its own realm when chambered in a rifle. Chambering it in the AR platform created some challenges that required us to rethink how the .500 S&W could best be solved by slight changes in the case design. Removing the rim allowed it to work properly in existing detachable box magazines. The result of this is the .500 Auto Max cartridge.

This cartridge was the impetus used to shift the company from being a lever-action heavy gun maker to getting into the AR platform. Sure, it’s a niche market with these big bores, but there’s definitely a definite market for it out there.

The bullet diameter of the 500 Auto Max is 0.5 inches. Bullet weight varies from 275 to 700 grains, and of course your felt recoil and how long you run the gun is going to depend on which load you choose. Companies like Buffalo Bore and Underwood mostly make 350 to 440 grain bullets which do just fine for target shooting and hunting alike.

How does the AR500 Auto Max Pistol shoot? How hard does it kick?

If you like big bores, this is what would be considered the fun part. Lucky for me, I do love ’em. I’ve run a variety of ammo through the gun including Buffalo Bore 500 Auto Max 350 grain JHP and Underwood Ammo 500 Auto Max 420 grain Xtreme Penetrator. If you prefer to handload, there are plenty of components out there, so you can do that, too.

I won’t sugarcoat it, The 500 Auto Max launched from an AR pistol platform generates significant recoil (it does the same from a rifle, too). You can learn to brace yourself and handle it, but the amount of felt recoil means this is not a gun for all shooters. Even so, the AR500 Auto Max is seriously fun to shoot (yes, really).

At the range it’s accurate on paper, although it isn’t a precise gun. If you’re hunting it’s utterly devastating on feral hogs, which makes it a winner for me. Technically you could use it on deer but realistically it’s better left as a predator and varmint gun.

If you want to use this as a truck gun or for home defense, you could, but it’s really more of a fun day at the range gun. That, as well as a great tool for controlling sounders of hogs. But if you decide you need a .50-caliber bullet for some sort of personal defense use, take the time to figure out penetration and overall performance. You’re responsible for every bullet you send down-range.

AR500 handguard
Thanks to the abundance of Picatinny on the gun’s handguard it’s easy to add whatever aftermarket accessories you want. (Photo credit: Kat Ainsworth Stevens)

Is the AR500 Auto Max Pistol Right for You?

This is basically the ultimate big bore AR platform pistol. I find it to be a great fit to keep on hand driving fencelines and filling feeders because it’s crazy effective on hogs, coyotes, and badgers. And because it’s a pistol rather than a rifle, it’s easier to maneuver. You just have to get used to managing that recoil.

If you have the love of big bores or the desire for a larger caliber truck gun, this is the gun for you. Go ahead, add a true big bore AR pistol to your collection. You know you want to.

 

Specifications: Big Horn Armory AR500 Auto Max Pistol

Caliber: 500 Auto Max
Capacity: 5+1 (9 round magazines available)
Barrel Length: 10 inches
Muzzle: Threaded
Trigger: Match Grade RISE Armament Rave 140 trigger, single stage 3.5 lb pull
Weight: 8.1 lbs.
MSRP: $2,599

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1 thought on “Big Bore Goodness: The Big Horn Armory AR500 500 Auto Max Pistol”

  1. I Haz A Question

    Intriguing and something I wish I could have (alas, CA and all that), but I imagine you’re going to want to put something on the end of that buffer tube (stock, heck even a tennis ball at the minimum) to keep it from causing some real pain to your body as the force of the cartridge firing slams it into you.

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