Sig Sauer designed the ultra-versatile SIG556xi Russian to run 7.62x39mm ammo, and users can swap out the barrel, forend, stock and even the lower for a 5.56mm NATO version if so desired.
Sig Sauer equips the SIG556xi Russian with some unique features, including a polymer, side-folding buttstock with a removable cheekpiece.
Note the three-prong flash suppressor.
SIG556xi ambidextrous safety.
The M-15 Light Tactical Carbine (LTC) from Armalite provides shooters with a versatile, hard-hitting modern sporting rifle chambered for the 7.62x39mm. With features such as a 16-inch, chrome-lined, chrome-moly barrel, a 10-inch, free-floating KeyMod handguard, a low-profile gas block, a six-position-collapsible buttstock and a crisp, single-stage trigger, the M-15 LTC is a truly versatile design. Weighing in at just 6.2 pounds unloaded, the 7.62x39mm M-15 LTC is the perfect choice for anyone appreciating simplicity, value and quality features in their AR. (armalite.com; 800-336-0184)
Affectionately called the Mutant, the Mk47 AKM from CMMG is an AR-style rifle that uses AK magazines and shoots the 7.62x39mm round. Offered in various configurations, there is a Mutant to meet everyone’s needs. This specific model has a 16.1-inch barrel and weighs in at a little more than 7 pounds. The handguard has KeyMod attachment points, and Magpul provides the adjustable stock, pistol grip and magazine. I’ve previously tested this rifle and found it to be reliable and solidly built. Its accuracy was very good, and it worked with every surplus AK magazine I could find.
Rifles from MGI are seemingly half firearm, half shapeshifter. Using a special design, these AR-style rifles are designed to quickly swap barrels, bolts and magazine wells so that a single rifle can convert to any number of rifle or pistol cartridges. One of the basic configurations is in 7.62x39mm. This rifle uses surplus metal AK magazines as well as newer polymer ones. Versions are available with a low-profile gas block or A2-style front sight base (shown). The gun weighs in at less than 7 pounds and comes with an adjustable buttstock.
Patriot Ordnance Factory, or POF-USA, has made a name for itself by making reliable AR-style rifles that use a gas piston operating system in addition to direct-impingement designs. With the 7.62x39mm Puritan, the company gives customers the option of which operating system to use. With AR-style magazines, the gun retains the push-button magazine release and other controls standard to AR rifles. POF-USA appoints these rifles with Magpul furniture, a drop-in trigger and E2 dual extraction technology. The bolt carrier group is nickel-boron coated, and the rifle has a special anti-tilt buffer tube.
Rock River Arms (RRA) makes a series of rifles that use AK magazines and run the 7.62x39mm cartridge. These guns are available in a variety of configurations, and the X-series rifles are the top of the bunch. Fitted with an 18-inch, fluted, cryogenically treated barrel equipped with RRA’s Beast muzzle brake, the LAR-47 X-1 is distinctive and immediately recognizable. Surrounding the barrel is RRA’s TRO-XL free-floating handguard. The rifle comes with black or tan furniture, including RRA’s Operator A2 or CAR stocks.
The 7.62x39mm SRC from Windham Weaponry looks and runs like a traditional AR-15. However, the larger-caliber ammunition changes the dynamic whether in the field or in a more tactical role. This gun uses a 30-round magazine with a substantial curve that operates in a manner consistent with traditional AR magazines. It is equipped with a low-profile gas block and can be set up with iron sights, optics or both. Traditional handguards with heat shields, a pistol grip and a six-position stock give the gun a classic look.
From the battlefields of Vietnam to modern wars abroad, derivatives of the AR-15 and AK-47 platforms continue to face off in violent confrontations between the forces of liberty and those representing totalitarianism.
Although they are vastly different, each rifle system has proven its worth during decades of combat.
Both the AR and AK systems have exemplary features…and a few weaknesses. Though I believe the weaknesses are often exaggerated, the two guns do appear to be opposites in many regards. Where one is weak, the other seems strong. Sig Sauer apparently recognized the same thing and has attempted to blend the best features of both guns into a rifle system that is greater than the sum of its parts. Say hello to the SIG556xi rifle.
More than a simple mashup of the AR and AK platforms, the SIG556xi rifle also brings in many of the outstanding features of the Swiss 550 series of combat rifles. From these inspirations the company made a modular rifle that can run 5.56mm ammo from AR mags or 7.62x39mm rounds from AK mags. For this test, I got my hands on a SIG556xi rifle chambered in the classic Iron Curtain cartridge.
Comrade In Arms
Let me start by saying that the rifle I received was well-built and felt great in my hands. For me, the gun’s balance was superb, and using the rifle felt very natural. Its fit, finish and feel all received top marks.
Sig Sauer’s SIG556xi rifles are largely modular, meaning the shooter can easily mix and match parts. My SIG556xi Russian came with a Swiss-style folding stock, a 16-inch barrel chambered for the 7.62x39mm, a lower that accepts most AK-style magazines and a polymer handguard. However, with this design I can easily swap out the stock or barrel for others that better suit my needs. The lower receiver can also be changed to one that accepts AR magazines to match a 5.56mm NATO barrel, for example. I can also replace the handguard with an aluminum one.
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Sig Sauer built this rifle so it’s easy for any shooter to operate. The controls are truly ambidextrous, and brass does not hit you in the face no matter which shoulder you shoot from.
AK-type rifles have a nearly mythical reputation for reliability. While Sig Sauer did not design this rifle to compete with AK-47/AKM rifles, and Swiss 550 series rifles are legends in their own right, the caliber and magazines will nevertheless cause shooters to make comparisons between this gun and the AK.
While on the range, I put roughly 500 rounds through the gun. The ammunition was a mix of premium U.S.-manufactured loads and a significant amount of steel-cased Wolf Performance ammunition. Throughout it all, I experienced only one problem. After about 200 rounds of shooting, I had a failure to feed with the Wolf load. I cycled the bolt and shot another 300 rounds without additional problems.
I enjoy shooting AK-style rifles, but I have to admit that the ergonomics of the SIG556xi were a significant improvement. Sig Sauer includes a removable cheek riser on the stock that was perfect for aligning my eye with the sights. Even with my increasingly unreliable eyesight, I managed sub-3-inch groups at 100 yards using an improvised front rest with all of the ammunition I ran. The best group of the bunch came with Hornady’s SST rounds, but even the inexpensive Wolf Military Classic load was suitably accurate for most purposes. With glass, a shooter could tighten the groups up even more.
The recoil was mild, and I could keep multiple rapid-fire strings on target with relative ease. I added a Trijicon MRO reflex sight to the gun to test its speed and accuracy at close range. The ergonomics of the gun combined well with the visibility of the sight to make easy work of close-in shooting. The MRO also worked well for shooting at longer distances.
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Magazine compatibility is the only potential issue, and the problem can’t be entirely blamed on Sig. The AK-47/AKM platform has been in production for nearly 70 years in a seemingly unlimited number of models, factories and countries. With that much time and variation, tolerances fluctuate, and some parts simply don’t fit some guns. Making a receiver that can take “Magazine A” might mean it is too tight or too loose for “Magazine B.”
I found that the SIG556xi Russian leaned toward being tight rather than loose when it came to magazines. The included 30-round TAPCO magazine worked perfectly, as did the surplus metal magazines from Poland and Egypt that I had on hand. However, I tried a variety of 10- and 30-round TAPCO magazines from different manufacturing lots and discovered that none of them would fit. I determined that if I filed down the ledge on the back of the TAPCO magazine body where the latch hooks onto it, then the magazine would work. It was still tight, but it would feed and function properly.
The SIG556xi Russian is a high-end rifle that is suitable for virtually any mission where you might need to employ the medium-power 7.62x39mm cartridge. From a treestand to a perimeter position on a SWAT callout, I would happily carry this rifle. With any of the top loads in this caliber, the SIG556xi Russian is a credible defensive tool that’s worth your time and consideration.
Although the SIG556xi is unique in the firearms industry, it is certainly not the only rifle to share characteristics of both the AR and AK rifle platforms. Scroll through the gallery above to get a look at six other rifles that blend the two opposing worlds.
For more on the rifles featured in the gallery above, visit the following sites.
Rock River Arms
This article was originally published in the October/November 2016 issue of ‘Guns & Weapons For Law Enforcement’. For information on how to subscribe, please email [email protected]
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