Big Horn Armory AR500 in 500 Auto Max Now Available

The Big Horn AR500 in 500 Auto Max.

Big Horn Armory announced this week that its AR500 chambered in 500 Auto Max is now available!  This is the world’s most powerful short-range semi-automatic rifle in the world.

Based on a DPMS-style AR in .308, the Big Horn AR500 is gas operated and features a lightweight aluminum receiver, all steel parts replete with a nitrite finish, and an 18-inch threaded barrel.

“All we do at Big Horn Armory is design and make big bore guns,” Greg Buchel, president of Big Horn Armory, said in a press release.

“Using the 500 S&W magnum cartridge as our springboard, we wanted to bring back the concept of hunting using big bore cartridges for the simple reason it puts game down immediately, regardless of the bullet’s construction or speed,” he continued. “As hunters ourselves, our goal is to bring game down efficiently and ethically.”

SEE ALSO: A .500 Magnum Lever-Action? The Big Horn Armory Model 89 Brush Buster! Full Review.

Big Horn developed the 500 Auto Max by using a 500 S&W rimless straight-walled casing.  The company says it is capable of feeding and firing any .500 diameter bullet between 200 and 700 grains.  Given the variety of loads, Big Horn says the 500 Auto Max can easily exceed 4,000 FPE.

Purchasers can find 500 Auto Max from Buffalo Bore and Underwood Ammo as well as on Midway USA.


  • Caliber: 500 Auto Max
  • Rate of Twist: 1 in 24
  • Barrel Length: 18 inches
  • Muzzle: Threaded
  • Crown: Recessed
  • Butt Stock: Adaptive Tactical EX Performance M4-style stock of high-impact polymer, collapsible and adjustable
  • Foreend: MLOK with full Picatinny rail
  • Action Materials: 7075 Aluminum hard anodized
  • Metal Finishes: Hunter Black Nitride on SS parts
  • Swing Swivel Mounts: Integral front and rear
  • Mag Capacity: 5
  • Length of Pull: Adjustable
  • Overall Length: Varies
  • Weight: 9.55 lbs.
  • MSRP: $1,999.00

As mentioned Big Horn developed the AR500 primarily for hunting big game.  Though, that doesn’t mean it wouldn’t work well for law enforcement or military.  Given the wallop of the round, it would serve as a quality breaching tool or even a runaway truck stopper.

MSRP for the AR500 is $1,999.  For more information visit

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About the author: S.H. Blannelberry is the News Editor of GunsAmerica.

{ 5 comments… add one }
  • Dennis McKibben February 1, 2019, 11:54 pm

    I have an AR-10. Can I purchase the AR-500 upper?

  • J. Smith June 22, 2018, 1:10 pm

    The only real hunting cartridge is a .50 BMG. Im just sad we cant use a 20mm to hunt.

  • James Appleyard June 22, 2018, 8:00 am

    that’s not too bad for a cold Big Bore. looking forward to getting one soon. Keep up the good work

  • Cary Kieffer June 22, 2018, 7:58 am

    I’ve been looking at these awhile. They make some amazing energy with all that extra barrel over my 500 Smith revolver. Here’s the thing though, of the literally 18 AR’s in my pile, I’ve built them all. I dont want to buy a rifle, I would LOVE to buy their barrel and bolt…preferably a 14.5 I can perm attach a brake too. I dont know if their mag is proprietary or not but if so, buy those too. In short, I hope Big horn decides to sell a “builders kit” with assorted barrel lengths. I talked to them awhile back, a Mr. Sam Kuntz, nice guy but at the time it was a no go on building your own. Love the idea of this, if you cant drop it quickly with one of these you should have stayed the hell away from it

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