(Originally published 11.03.2017, Updated 01.08.2024)

Our videos on the SSK Industries rifle chambered in .950 JDJ, a.k.a. “Fat Mac” are two of the most popular we’ve ever made. They date back to 2017 when Fat Mac first came to us and the temptation to shoot him was too great to resist.

Rock Island Auction Company has had the pleasure to offer numerous firearms from gunmaker, cartridge designer, and SSK Industries founder J. D. Jones, including a McMillan Bros. bolt action rifle in 14.5 JDJ and an MMCI bolt action rifle in .700 JDJ. But both are dwarfed by the mighty .950 JDJ.

A McMillan Bros. bolt action rifle in 14.5 JDJ (left) and an MMCI bolt action rifle in .700 JDJ (right).

February, 2024 saw the return of SSK Industries .950 JDJ “Gun Number One” to Rock Island Auction Company, one of only three of these titanic bolt action rifles ever manufactured. Let's take a look at this titan in depth.

The .950 JDJ. SSK Industries manufactured only three impressive rifles chambered for .950 JDJ.

Features of the .950 JDJ Fat Mac Rifle

The .950 JDJ Fat Mac was developed by the cartridge’s namesake and president of SSK Industries, J.D. Jones. It is 20x110mm Vulcan Cannon cartridge shortened and then necked down to .950 caliber. The .950 JDJ is so large it had to receive an ATF “Sporting Use Exception” from the ATF to avoid being classified as a Destructive Device. Only three rifles were made by SSK to fire this mammoth round.

An incredibly massive SSK Industries .950 JDJ bolt action rifle for sale.

The .950 JDJ Fat Mac is one such rifle. Absolutely pushing the boundaries of small arms, this massive single shot collector firearm is host to a collection of features designed to mitigate its powerful recoil. First, it is bedded in a bench rest stock, so shooters can more easily utilize a shooting platform of sorts. Second, the .950 JDJ rifle is fitted with a gargantuan muzzle break, nearly as large in diameter as a 2-liter soda bottle. Lastly, this leviathan long gun tips the Toledos at a whopping 61 pounds! No wonder it needs a bench rest stock.

Made by SSK Industries, the .950 JDJ Fat Mac is the largest sporting rifle ever made. The cartridge began as a 20mm Vulcan round, cut down to 70mm case length and necked up to 24mm (.95 caliber).

Shooting the .950 JDJ Fat Mac

With a gun this rare and powerful in-house, it was only a matter of time before the desire to shoot it became insurmountable. One beautiful fall afternoon I was fortunate enough to take the .950 JDJ Fat Mac out to a private range along with the other two monster rounds shown in the photo below.

L to R: .30-06, .700 Nitro Express, .950 JDJ, and 4-Bore rounds. JD Jones’ .950 JDJ cartridge is generally described as the largest sporting rifle cartridge ever produced.

The .700 NE was fired from an immense Searcy & Co. double rifle and the 4-bore was thrown from a beautiful crafted Ken Owen double rifle. To say it was an amazing morning is an understatement. Check out our video posted at the top of this blog where we shoot some of the world’s most powerful collector firearms.

Two monsters for sale at Rock Island Auction Company, including an SSK Industries .950 JDJ bolt action rifle (top) and a McMillan Bros. 14.5 JDJ bolt action rifle (bottom.)

So how was it? Not as “shoulder wrecking” as one might think. Obviously, and as one can clearly see in the slow-motion footage, these rifles pack a wallop! Their booming report is more akin to artillery than to a rifle. But what about their recoil? Let’s describe them one-by-one.

700 Nitro Express

This is a powerful rifle to be sure! Literally, people have used smaller rifles to kill elephants. Think about that for a second. All things considered, the recoil is quite manageable. No bruising, no marks made by clothing, and no tingling or ache in the shoulder area.

A massive engraved B. Searcy & Co. Double Rifle in .700 Nitro Express.

If you are someone who bruises easily, your mileage may vary. While enough to elicit your favorite expletives upon firing, for me there were no negative effects on the body after firing. Five seconds after the fact, as far as my body knew, I might as well have fired a .30-06. Excepting of course for my ridiculous grin and the tangible excitement coursing through my veins. No doubt the rifle’s 17 pounds and generous recoil pad helped to dull the vigorous kick.

The dual .700NE bores relative to the size of a quarter.

4 Bore Double Rifle

Here was the bad boy of the bunch. Modeled after a rifle made for the Maharaja of Rewa, India, this rifle was made by gunsmith Ken Owen of Memphis, Tennessee in the early 1990s. He produced only six such rifles and is quoted as stating each massive double rifle took approximately 1,000 man hours to produce. A quick glance gives an immediate impression: it’s short, stocky, beautiful, and my-god-how-big-are-those-barrels?

A Ken Owen "Owen-Rewa" 4 bore double rifle, one of the most powerful double rifles around.

After much prepping and adjusting, and a quick farewell to my rotator cuff, a light squeeze of the trigger unleashes an absolute lightning strike. It throws the shooter back about as far as the .700 Nitro Express, but the sensation is markedly different and more powerful. In fact, this was the only rifle fired that day where the sensation of the recoil didn’t end after the shot. The shoulder tingled for some time after.

In the Owen-Rewa 4-bore double rifle, a quarter can fit comfortably in the muzzle.

Think of it this way. After you fire a hunting rifle or a military surplus collector firearm, you fire and then the sensation is finished. You walk away no different. Now imagine you have asked a good friend to haul back and slug you where you normally position the butt of a rifle or shotgun. That sensation doesn’t end as soon as the punch does, it lingers. The same can be said for the 4-bore and its cordite-powered punch.

The .JDJ Fat Mac

Finally, we got to the .950 JDJ Fat Mac. It was the fattest round of the day fired by the largest rifle of the day. Dealing with this much power, we were absolutely treating this rifle with the utmost respect.

Say hello to Fat Mac, a behemoth of a rifle chambered in .950 JDJ.

After constructing a make-shift “sled” out of sandbags and bags filled with lead shot, we securely positioned the .950 JDJ rifle. The bolt was removed, the round placed gently in its claw, and both were then slowly inserted into the rifle. After giving the bolt a gentle turn, everything was locked into place and we were ready for whatever this rifle had in store.

Where else can you find an SSK Industries .950 JDJ Gun bolt action rifle for sale? The barrel is marked "SSK 950 JDJ Gun Number One" in fancy script lettering on the left side.

It was rather surprising when the .950 JDJ Fat Mac produced the most manageable recoil of the day. Then again, when you consider all the recoil-dampening features listed earlier, perhaps it isn’t so surprising after all. Despite requiring all the brass to be custom-made and the rounds to be handloaded, this is a gun that you want to shoot until the ammo is gone. If only we had more time with Fat Mac to test its power on a wide variety of unsuspecting and unusual targets.

The SSK Industries .950 JDJ Fat Mac "Gun Number One" (left) and a McMillan Bros. 14.5 JDJ rifle (right.)

What Does it Take to Own a .950 JDJ Fat Mac?

Only money and an account with Rock Island Auction Company. Since the ATF granted a “Sporting Use Exception” for it to be created, no NFA paperwork is required to own the .950 JDJ. Typically, any firearm that fires a projectile over .50 caliber would necessitate being registered as a “destructive device,” but whoever takes home Fat Mac can keep the $200 required to do that and spend it on reloading tools instead. This powerhouse rifle requires no special licenses, no registration, no training courses, no permits, and no tax stamps. Hooray for America!

The .950 JDJ rifle weighs in at a scale-breaking 61 pounds!

SSK Industries manufactured only three of these juggernaut rifles, and as of 2014 SSK no longer produced .950 JDJ ammunition. Fortunately, the example offered at Rock Island Auction Company includes two reloading dies, approximately 15 loaded rounds, 63 empty casings, two wood loading blocks, and nearly 90 cast lead bullets.

The .950 JDJ (shown here next to 5.56mm and 9mm cartridges) was based on the 20x110mm Vulcan Cannon cartridge, shortened, and necked up to match a .950 caliber (24.1mm) cast lead bullet. The original loading was a 2600 grain (168g) cast bullet moving at 2200 fps (670m/s), for a whopping 28,000 foot-pounds of muzzle energy. There are some antitank rifles that produce more, but nothing comparable in both energy and bore diameter in the sporting realm.

Oh, and for those who don’t have an account yet to bid with Rock Island Auction Company, what are you waiting for? There are tens of thousands of collector firearms sold each year in reach of every budget. Subscribe to the Rock Island Auction newsletter for more gun blogs and gun videos covering the heavy hitters of the firearms world, including the 10 gauge shotgun, the Barrett M82 .50 BMG, the punt gun, the Gatling gun, and more.

Brandon Herrera fires the M82A2 in .50 BMG.