7 Mutants: Blurring the Lines Between ARs and AKs

By Robert Sadowski published on in Firearms

At one time, AR-15 and AK-47 designs were black and white. They were easy to identify by sight and sound because they fired their own specific cartridges using their own specific operating system. Today, that clear black-and-white demarcation is gone, replaced with a range of alternative rifles that use varying qualities of each platform to make new mutants, hybrids, mongrels, oddities, novelties, or whatever you want to call them.

The variations can be simple, with something like Bushmaster’s XM-15 M4 Patrolman’s Rifle being fitted with a 7.62x39mm chamber and barrel or Huldra Arms’ Mark IV shooting the 5.45×39 round. Or the mixing can be as minor as adding an “R” to an existing model; e.g., when SIG Sauer rechambered the SIG556 in 7.62×39 Russian to make the SIG556R. Windham Weaponry’s 7.62x39mm SRC and Rock River Arms’ LAR-47 likewise use the 7.62×39 and accept AK-style magazines. But the ceiling is much higher. Faxon’s ARAK-21 line combines elements like modular receivers with the AK’s operating system. CMMG’s hot new Mutant takes its mixing to such a level that the company calls the Mk47 a new rifle platform.

There are many more variations on this theme, but for now, we looked at seven makers’ guns in more depth, ranging roughly from “most” to “least” in their amount of mutation, in our humble estimation:

CMMG Mk47 Mutant AKM

CMMG Mk47 Mutant semiautomatic rifle

The Mk47 MUTANT was recently announced and is literally a mutation of the AK and AR designs creating an all-new rifle platform.

The Mk47 MUTANT was recently announced and is literally a mutation of the AK and AR designs creating an all-new rifle platform. The upper uses a bolt carrier group derived from the massive AR-10 bolt carrier group. The 16.1-inch free floated barrel has a 1:10 twist. The lower is manufactured from 7075-T6 billet aluminum and designed to accept almost all existing AK magazines with a standard ambidextrous magazine latch system. The platform runs on a carbine-length direct-impingement gas system. The Mk47 comes optics-ready with a full-length Picatinny rail along the top. Weight of the rifle is just over seven pounds. Trigger assembly, grip, handguard, buttstock, buffer-tube assembly, muzzle brake, and gas system are fully interchangeable with mil-spec AR15s.  Click Here to Start Shopping Online at Cheaper Than Dirt

 

 
CMMG Mk47 Mutant
Action Direct impingement, semiautomatic
Barrel Length 16 inches
Caliber 7.62x39mm
Overall Height height in inches; use decimal numbers
Weight Unloaded 7.2 pounds
Sights Optics-ready accessory rail
Stock or Grip Collapsible Magpul CTR
Capacity 30

Faxon ARAK-21 XRS

Black Faxon ARAK-21 XRS rifle

The ARAK-21 XRS combines AR design features with the AKs long-strong piston operating system.

Faxon has been making a truly modular rifle for years. The ARAK-21 XRS combines AR design features —modular lower and upper receivers — with the AK’s long-stroke-piston operating system. The monolithic upper has a four-position switch allowing variable settings, including single shot, and mates to any mil-spec AR lower. It features dual forward recoil springs and dust cover, and the ambidextrous charging handle folds and is nonreciprocating. The ARAK-21 XRS system is designed for fast barrel/caliber change and can include three barrels, 5.56 NATO, 300 BLK, and the recently added 7.62×39 chambering. (FaxonFirearms.com; 513-674-2580)

 
Faxon ARAK-21 XRS
Action Semiautomatic
Barrel Length 16 inches
Caliber 5.56mm NATO, 7.62x39mm, .300 AAC Blackout
Overall Length 33 to 36.5 inches
Weight Unloaded 7.6 pounds
Sights Optics-ready rail
Stock or Grip 6-position
Capacity 30

Windham Weaponry 7.62x39mm SRC

Windham Weaponary black rifle chambered in 7.62x39mm

This AR rifle is designed to operate with the 7.62x39mm Russian cartridge.

The Windham Weaponry 7.62x39mm SRC is not an ordinary AR-15. Notice the distinct, bent curve of the 30-round magazine that looks suspiciously like an AK magazine. This AR-15 rifle is designed to operate with the 7.62x39mm Russian cartridge. The barrel is manufactured from 4150 chrome moly vanadium 11595E steel and uses a 1:9.5-inch right-hand twist. The forged upper and lower receivers are mil-spec, as is the enhanced bolt designed for use with the 7.62x39mm — but it is still made of Carpenter 158 steel per U.S. mil-spec. (windhamweaponry.com; 855-808-1888)Click Here to Start Shopping Online at Cheaper Than Dirt

 
Windham Weaponry SRC
Action Semiautomatic
Barrel Length 16 inches
Caliber 7.62x39mm
Overall Length 32.3 to 36.1 inches
Weight Unloaded 6.2 pounds
Sights Optics ready
Stock or Grip M4 6-position
Capacity 30

Rock River Arms LAR-47 Delta Carbine

Black rifle, the LAR-47 from Rock River Arms

The LAR-47’s lower accepts AK-style magazines.

The LAR-47 is finally coming into production after Rock River teased us with it a year ago. The proprietary lower is forged and designed to accept AK-style magazines. The magazine release is ambidextrous. The barrel has a 1:10 RH twist rate. The forged upper is similar to a typical AR-15, allowing users to use aftermarket handguards. The LAR-47 comes equipped with an RRA 6-position Delta CAR buttstock, Ergo Suregrip pistol grip, and RRA two-piece quad handguard. (rockriverarms.com; 309-792-5780)

 
Rock River Arms LAR-47
Action Semiautomatic
Barrel Length 16 inches
Caliber 7.62x39mm
Overall Length 36.5 inches
Weight Unloaded 7.8 pounds
Sights Optics-ready rail
Stock or Grip RRA 6-position Delat CAR
Capacity 30

Bushmaster XM-15 M4 Patrolman’s Rifle

Bushmaster XM-15 rifle chambered in 7.62x39mm

This AR-15 from Bushmaster retrofits the 7.62x39mm cartridge seamlessly into the traditional AR platform.

This AR-15 from Bushmaster retrofits the 7.62x39mm cartridge seamlessly into the traditional AR platform. The rifle features a 16-inch barrel with an M4 profile. The bore and chamber are both chrome lined. An A2-style birdcage flash hider is threaded onto the muzzle. The furniture is standard M4 style — 6-position buttstock, pistol grip and handguard. The carry handle can easily be removed, allowing a user to mount a red dot or reflex-style sight. It a plain-Jane basic AR that speaks Russian. (Bushmaster.com; 800-998-7928 )Click Here to Start Shopping Online at Cheaper Than Dirt

 
Bushmaster XM-15 M4 Patrolman’s Rifle
Action Semiautomatic
Barrel Length 16 inches
Caliber 7.62x39mm
Overall Length 32.8 inches
Weight Unloaded 6.6 pounds
Sights Adjustable, removable carry handle
Stock or Grip M4 6-position
Capacity 30

Huldra Arms Mark IV 5.45x39mm Carbine

Black rifle

This AR uses a patented gas piston that allows the carbine to run cooler and cleaner than the typical gas impingement system.

This AR uses a patented gas piston that allows the carbine to run cooler and cleaner than the typical gas impingement system, and is chambered in 5.45x39mm. Accuracy is 1 MOA at 100 meters. The chrome-moly-vanadium barrel has a 1:8 twist rate, an M4 profile and employs M4 feed ramps. The Mark IV comes with an M4 style handguard and is optic ready with either a low-power scope or red dot sight. (huldraarms.com; 218-829-3521)

 
Huldra Arms Mark IV
Action Semiautomatic
Barrel Length 16 inches
Caliber 5.45x39mm
Overall Length 32.3-35.6 inches
Weight Unloaded 6.2 pounds
Sights Optics-ready rail
Stock or Grip MIL-SPEC 6-position
Capacity 30

SIG Sauer SIG556R

SIG Sauer's 556 rifle with foldiing stock

The SIG556 is the civilian version of the legendary Swiss-designed series 550 combat rifle.

The SIG556 is the civilian version of the legendary Swiss-designed series 550 combat rifle. The 556 uses a gas-piston operating system and rotating bolt. The SIG556R—the “R” is for Russian—takes the rifle’s reputation for performance, accuracy and durability and chambers it in 7.62x39mm. The 16-inch barrel features a twist rate of 1:9.5 inches and has four-groove rifling. The gas valve is adjustable to match the ammo. AK-style magazines are compatible with the SIG556R, yet is retains the Swiss folding stock, allowing the rifle to go from 35.9 inches with stock extended to 26 inches folded. (SIGSauer.com; 603-610-3000) Click Here to Start Shopping Online at Cheaper Than Dirt

 
SIG Sauer 556R
Action Semiautomatic
Barrel Length 16 inches
Caliber 7.62x39mm
Overall Length 35.9 inches
Weight Unloaded 7 pounds
Sights Optics-ready rail
Stock or Grip Folding, fixed
Capacity 30

Which rifle is your favorite? Tell us which one and why in the comment section.

Robert Sadowski has written about firearms and hunting for nearly 15 years. He’s authored four gun books and edited three and is a contributor to numerous gun-enthusiast magazines, including Combat Handguns, Black Guns, Tactical Weapons for Military and Police, Gun Tests, Personal and Home Defense, Gun Hunter, SHOT Business, and others. He has a personal affinity for large-caliber revolvers and the AR platform.

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Comments (21)

  • Joe Basta

    |

    You Forgot MGI Hydra in 7.62×39!

    Reply

  • Jerry

    |

    Since the companies have adapted the 7.62×39 to the AR platform, why not the 7.62×54 to the AR-10 platform?? You’d have millions of Mosin users chomping at the bit to have a semiauto that could hunt longer distances. I’d buy one in a New York…well sorry a Missouri minute!!

    Reply

  • Bill

    |

    Do you have anything in this form factor chambered for 7.62x54r ? Ideally it would be piston driven due to the corrosive nature of milsurp ammo. However, since the AR form factor is fairly easy to keep cleaned and oiled, the piston / direct gas issue is certainly negotiable.

    The only reasonably priced semi-automatics I have found in this caliber so far is the VEPR (at around $900) or the Romanian PSL (~$800), but it is based on the AK pattern, not the AR, and apparently has an imported magazine limit of 10. Pretty much need more capacity for three-gun competitions and tactical training / competitions.

    If I, a relative newbie to shooting, am interested in purchasing such a rifle, likely there is a decently sized market out there for something in this design and caliber … and also for domestically made larger capacity magazines for the VEPR and PSL Ak variants.

    Reply

  • Peter

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    Still waiting on my Joshua. Seems like the best hybrid out there.

    Reply

  • 10-ring

    |

    Your right Peter, he did forget the Joshua, but I did not expect to see it listed as it has seen low production #’s so far(around 100) and most people are not aware of it yet.I waited 2 years for mine not knowing if I would ever see it.But it finally arrived in January.

    Reply

    • Peter

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      I’m waiting on their versatile “triple play”. Hard to believe it has 1 minute barrel change capability to go from 5.56 to 7.39 to 300 Whisper. All carried in a Pelican breakdown case!

      Reply

  • Eric M

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    Well put Travis, well put.

    Reply

  • Peter

    |

    You forgot Amendment Arms Joshua MK 5

    Reply

    • Bob

      |

      I love my Joshua MK5. The 5.56 rounds just rollout without any problems. Nice and easy to lean. Lots of sling points and rails come on the MK5. Not like my AR. Very good workmanship on the whole thing.

      Reply

    • Bob

      |

      The barrel is held by a set screw with a hex socket head. Loosen that screw and the barrel just unscrews. A lot of in threads very well done and the barrel with the rails is off. You have to pop the top rail off, remove the long spring and then you can pop the bolt out. I found that putting it back together that I had to depress the hammer to get the bolt assembly to slide in. Not a problem when you know but took a while to discover. The whoe thing comes apart in just a couple of minutes. Wow! Net!

      Reply

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