Big Horn’s AR500… a T-Rex Thumper

Worried about taking on a flock of T Rexes and want a lightweight rig to bolster your confidence? Well, Big Horn Armory’s AR500 Auto Max just might fit the bill.

It’s funny, need I say strange, the things that can run through a writer’s mind when trying to start an article… for some reason a remix of Sir Mix-A-Lot’s 1993 Grammy-winning, double platinum Baby’s Got Back hip-hop tune started playing in my head when pondering Big Horn Armory’s half-inch-bore AR pistol. I thought it might be fun to write a lyrical parody of the hip-hop song featuring this manly pistol, but after I read through the song’s original lyrics I had to stop and take a mental shower. To halt the song playing in my head, I got up from my laptop and went to refill my coffee cup….

Big Horn Armory, the Cody, Wyoming, rifle maker specializing in crafting .500 caliber lever-action rifles, decided to delve into the AR market. When they jumped in this overcrowded gun niche, their “go big or go home” approach left them with the “the most powerful AR on the market,” in their own words.

“We like to think BIG at Big Horn Armory. As a result, we’re not your average gun manufacturer. Since we’re gun guys like you, we only build guns that give us a reason to jump out of bed in the morning. For us, that means the bigger the better. Whether it’s packing 36,800 ft.-lbs. of energy in a lever action, or building the most powerful AR on the market, our goal is to give you the biggest bang for your buck. Literally. At the end of the day, that’s why we’re in the business. To build guns you can’t wait to shoot. We are so excited to have you join us on our quest to ‘Go Big or Go Home!’”

The Bullet

The 500 Auto Max is a rimless 500 S&W Magnum that offers shooters the option of buying factory fodder or reloading this behemoth. A very versatile cartridge, it can be had in in loaded ammunition with bullets ranging from 280 grains up to a hefty 600 grains. 

The handloader has even more options when utilizing bullets ranging from 275 grains to 700 grains. Bullet styles range widely, with, hardcast, jacketed hollow-points, monolithic solids, and more made available.

“This range of bullet weights and designs make the AR500 suitable for anything from prairie dogs to pachyderms to Peterbilts….”

This range of bullet weights and designs make the AR500 suitable for anything from prairie dogs to pachyderms to Peterbilts, which offers semi-truck-stopping power in a platform weighing less than 10 pounds.

To give you an idea of this pistol’s power, let’s dig into some basic energy calculations. bullet energy KE (in foot-pounds) is equal to the bullet weight (in grains) multiplied by the square of the bullet velocity (in feet per minute) divided by 450,437.

That being said, if you push a 440-grain Buffalo Bore flat-nose, gas-checked cast bullet out of this pistol at 1,650 fps, that yields a whopping 2,659 foot-pounds of energy. By comparison, a 240-grain .44 S&W Magnum factory load produces about 750 foot-pounds of energy. The insanely hot Buffalo Bore 340-grain Lead Flat Nose +P+ load launches at 1,425 fps from a 7 ½-inch revolver to produce 1,533 foot-pounds of energy.

Gun details

Big Horn Armory’s AR500 semi-auto pistol is based on their ground-breaking AR500 Rifle, the most powerful AR-platform firearm available. The AR500 Pistol is a large-frame AR chambered in 500 Auto Max. This cartridge in combination with their AR500 Pistol puts a lot of power into a pleasant shooting, rapid firing, exceptionally compact firearm. 

This combination of size, maneuverability and energy on target make the AR500 pistol easily accessible and ready to handle almost any situation.

“I like big guns and I cannot lie…”

Starting at the business end, this pistol sports a 10-inch Green Mountain barrel with a 1:24-inch twist. The muzzle is threaded ¾-28 TPI for an attached muzzle brake, or any other accessory you may wish to attach.

This pistol sports a top rail with full-length Picatinny slots for sight mounting. Fore and aft on the handguard it sports short Pic rail sections for more accessory mounting. A blade-style stabilizer is mounted on the recoil spring tube. An Ergo pistol grip helps manage recoil, too. An ambidextrous safety give easy access to either rightys or leftys.

Down Range

To wring this pistol out I mounted a Trijicon Ascent 1-4×24 scope for a little precision work. Later, I mounted a Trijicon RMR for a little more sleek outfit for moving and shooting on steel.

I managed to get my hands on two loads for the .500 Auto Max. The first was Steinel’s 280-grain Brass Spike. This load travels down the pipe of an AR500 rifle at 2,215 fps, but the pistol version sent these chunks of brass downrange at just a hair under 1,900 fps. At 50 yards this bullet’s best group measured 1.613 for five shots. Cut the distance in half and you’ll probably obliterate your aiming point with a tight cluster before you get to the fifth shot.

Steinel’s 280-grain Brass Spike produced a 1.613-inch 5-shot group at 50 yards.

The second load was a Buffalo Bore 350-grain jacketed hollow-point +P+ that travels from a rifle at 2,300 fps and produces 4,110 ft/lbs of energy at the muzzle. The shorter barrel of the AR 500 pistol will slow this round to an average of 1960 fps. At 50 yards, this load’s best performance put five rounds into a 1.435-inch group.

A scorching 350-grain jacketed hollow-point loaded by Buffalo Bore produces about 20% more muzzle energy than a 12 gauge slug, and it produced a 1.435-inch 50-yard group.

The AR 500 Auto Max pistol is an amazing piece of hardware when you start flinging soup can-sized projectiles down range. And, just as amazing is its inherent accuracy with a big thump on the receiving end. Check one out, you’ll be glad you did.

Big Horn Armory Relocates to Larger Manufacturing Facility in Cody, Wyoming

The new facility offers the power and space for BHA to operate additional machinery, as well as increase inventory storage space.

Big Horn Armory (BHA), makers of big-bore firearms, has completed the relocation of its offices and manufacturing facilities to 319 N. Blackburn St., Cody, Wyoming, 82414.

The new facility is over five times the size of the previous location, providing more manufacturing space to operate additional machines and better facilities for building BHA’s firearms. It also provides increased space for maintaining a larger inventory. These factors combine to make BHA’s operations run much more smoothly and efficiently than at the old facility and will aid in improving lead times in the next few months.

“The move to our new, larger facility offers expansion space for additional equipment and employees,” commented Greg Buchel, Owner of Big Horn Armory. “It will allow us to increase our manufacturing capabilities many times over what we could formerly accomplish. We look forward to supporting our local economy in Cody, Wyoming by creating many good, stable jobs within our company.”

BHA has increased its workforce in the manufacturing department by 20 percent since October 2021 and intends to double its staff by year-end. Nine new machines are anticipated to be on the manufacturing floor by the end of May 2022. All of the new equipment has CNC capacity with a mix of mills and lathes and barrel-making equipment, which will help to lessen the dependency upon outside vendors.

BHA has consistently been adding vendors over the past year and intends to add more. With a larger pool of sourcing suppliers, supply chain issues will be minimized and will help to reduce lead times on customer orders.

“We believe in building American-made, heirloom-quality firearms with attention to detail offered in unique, big-bore calibers and as such have invested in our manufacturing capabilities to match up with our beliefs,” Buchel stated. “We appreciate our customers’ patience during this relocation process. As we finish settling into the new facility, we continue to fulfill our orders and implement improvements to meet our customers’ needs. We anticipate reducing our lead times by half or better once we are 100 percent up and running.”

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