Sig Sauer SIG556R 7.62×39

As each new year comes and goes, firearm companies scurry to introduce the latest and greatest rifles to the marketplace. Some manufacturers are trying to fill an empty niche, while others are trying to find the solution to a problem. All the while, a few companies are turning out new models for no other purpose than to just have something new. Fortunately for the shooting public, when Sig Sauer introduces a new model, some serious thought has gone into the process.

Sig Sauer has been known for the quality of its AR-style rifles, which are offered in both direct-impingement and gas-piston versions. The company also manufactures the SIG550 series of rifles, which are based on the arms Sig originally produced for the Swiss military. In 2012, Sig Sauer introduced a new variant of the classic SIG550 series of rifles, the SIG556R. Some of our readers will be familiar with the time-proven SIG556, but may wonder about the “R” designation. The “R” stands for “Russian,” and denotes that this new variant is chambered in the 7.62x39mm cartridge.

The AK-ish Sig
The SIG556R is a semi-automatic, gas-piston-operated, magazine-fed carbine. Its 16-inch barrel features four-groove rifling with a 1-in-9.5-inch twist rate to get the most out of the 7.62x39mm cartridge. The piston operating system is contained underneath the forward handguard and consists of a gas block, gas tube, operating rod and recoil spring. The operation of the system is relatively simple and trouble free. Once the cartridge is fired, the gases propel the bullet down the bore. As the bullet passes the vent hole in the barrel, the gas is directed into the gas block, which drives the operating rod contained in the gas tube. The rearward motion of the operating rod pushes the bolt carrier, which in turn rotates and unlocks the bolt. The extractor on the bolt withdraws the empty case, which is then ejected. During this process, the recoil spring around the operating rod is compressed until the bolt carrier reaches its full travel. The recoil spring will then push the bolt carrier forward, stripping a new round out of the magazine and reloading the chamber. The final movement of the bolt carrier rotates the bolt, thus locking it in place.

Unlike a traditional AR, the gases are never directed into the action of the rifle, and the gas tube and operating rod may be removed for cleaning. As a reliability feature, the gas block contains an adjustable two-position valve. In its normal position, the valve allows the proper amount of gas into the system for the best all-around operation of the rifle. Should heavy fouling begin to effect functioning, the valve can be rotated to its second position to increase the gas flow until the rifle is cleaned.

Being chambered in 7.62x39mm, the SIG556R is equipped to use AK-type magazines, and the magazine release is located in the forward section of the triggerguard. A bolt catch is located on the left side of the rifle for use in locking the bolt to the rear, but unlike an AR, the bolt will not lock to the rear once the magazine is empty. The manual safety is ambidextrous and can be operated on either side of the receiver. Since the gas system is forward of the receiver, the rifle can be equipped with a side-folding stock that will not hinder operation of the rifle while folded. Overall, the SIG556R is a compact weapon that measures 35.88 inches long with the Swiss-style buttstock fully extended and only 26 inches when the buttstock is folded to the right side.

For Battle & Bucks
By now you may be wondering what justified the introduction of the SIG556R. There is a lot more to it than just wanting something new. By chambering the SIG556R in the 7.62x39mm cartridge, Sig Sauer filled an empty niche and found the solution to a problem that has plagued the AR family of rifles. This cartridge was developed for the AK-47 shortly after WWII, and for many years it was the cartridge of choice for the communist world. While the AK-47 has always been known for its extreme reliability, many versions of the AK have lacked in quality and accuracy. AR rifles chambered in this round have had the exact opposite problem. They have the manufacturing precision but have been questionable when it comes to reliability. The SIG556R fills a niche by supplying a rifle using the 7.62x39mm and still having both precision and reliability.

The SIG556R also solves the problem found in most ARs—its 5.56x45mm cartridge. People have questioned its power since it was first introduced, and many states will not even allow it to be used for hunting on anything larger than varmints. For many AR owners, this relegates their rifles to the gun safe when they’re not being used for target practice. The 7.62x39mm, however, fires a 123-grain, .30-caliber round at about 2,350 fps, which is more than suitable for medium-sized game such as whitetail deer. For those who will quickly mention the availability of AR-15s chambered in the 6.5 Grendel and 6.8 SPC, it only takes a few minutes of comparing prices to realize that the 7.62x39mm is the hands-down winner. Untold amounts of military surplus 7.62x39mm ammunition and current offerings on the marketplace make this cartridge one of the cheapest centerfire rounds available. The inexpensive surplus rounds can be used for practice and plinking, and quality hunting loads are available when needed.

Running The Russian
Before heading to the range to evaluate the SIG556R, I mounted Sig’s Mini Red Dot Sight (included with the rifle) on the rifle’s Picatinny top rail. (Backup iron sights, while available, are not standard equipment.) The top rail makes mounting optics a breeze, and Sig Sauer also ships the rifle with three short rail sections that can be attached to the handguard for mounting additional accessories.

While researching this rifle, I noticed a few statements on the internet questioning the reliability of the early production models. The comments were mainly about using a combination of surplus magazines and steel-cased ammunition. Since the ability to use inexpensive ammunition in this day of ammo shortages can be considered a boon, I gathered a supply of surplus steel rounds and magazines at a local gun show for my first range test. After using a few rounds to adjust the Mini Red Dot, I spent an entire afternoon and a few hundred rounds doing nothing more than checking the reliability of the SIG556R.

If you are expecting me to relate that there was not a single failure, I’m sorry to disappoint you. However, the only failures came when I was using a single aftermarket plastic magazine. Since I had picked it up at the show and there were no markings on it, I have no idea who made it. I can say that with the magazine that came with the rifle, and all of the surplus steel magazines, the rifle was 100-percent reliable. Also, keep in mind that I was using surplus, steel-cased rounds. All I can say is that, if there ever was a problem with this model, it has been corrected. The bad aftermarket magazine soon hit the trash bin, but the lesson I learned was well worth the $5. Check and test all of your gear before you have to depend on it, and remember that there is a difference between inexpensive and cheap!

The rifle handled rather well, and it took little time to adjust between it and my normal AR-pattern rifles. The buttstock comes with an extra spacer to adjust the length of pull, but I found it acceptable without its use. I also found that the Mini Red Dot worked rather well for out to 100 yards, but a scope would be required for true accuracy work. The trigger was the one point that I would like to see a little improvement. The two-stage trigger was smooth, but its travel and weight was more than I prefer.

My second trip to the range saw me equipped with a Leupold VX-R Hog 1.25-4x20mm scope and a few boxes of modern ammunition. Since the 7.62x39mm cartridge is in the same power range as the .30-30 Winchester, it should make a suitable cartridge for 100- to 200-yard shots on deer. At the same time, the low-powered Leupold 30mm scope is all of the magnification you should require. Leupold brought out this line of scopes in just the past couple of years, and I have found them to be outstanding optics for everyday use. The ability to push one button and have an adjustable red dot appear is more valuable than you could imagine. Precise shooting in low-light conditions is no longer a problem. The day found me testing soft-point hunting ammunition from Winchester, Remington and Federal. All of these rounds produced about the same results, with velocities hovering around 2,300 fps and three-shot groups ranging from 1.13 to 1.63 inches. I do believe, with a lighter trigger, this rifle would be capable of breaking the MOA mark.

On The Hunt
For the next couple of weeks, I spent a good deal of time at the range with the SIG556R and both the Leupold scope and Mini Red Dot. On the first day of deer season, my plan was to hunt from a stand with limited range. The Mini Red Dot was perfect for my opening-day setup. A young seven-pointer came over a low rise at about 40 yards and proceeded to feed on acorns within 20 yards of my stand. One shot and it never took another step.

For those trying to decide between an AR and an AK, your decision may be a little easier. The SIG556R can give you a rifle with quality and power. At the same time, you won’t have to put away your defensive carbine just because it’s hunting season. For those who aren’t taken by the concept of a black rifle in the woods, Sig Sauer’s very popular M400 is available in OD Green. Whatever you opt for, it’s safe to say that your hunting rifle will make an outstanding defensive weapon. Bottom line, there isn’t a reason to put your rifle away when the seasons change. For more information, visit sigsauer.com or call 603-772-2302.