Rifles > Semi-Auto

SIG Sauer's SIG516: Expect the Unexpected

SIG Sauer combined European engineering with the exceedingly popular AR platform.


A significant number of American shooters consider SIG Sauer to be primarily a handgun manufacturer. This is in direct contradiction to the fact that the company’s roots in Europe are tied to some extremely prolific and respected military and law enforcement rifle designs. SIG Sauer has been making bold moves in the past few years to remedy this misconception. In particular, the company’s SIG556 series of 5.56x45 mm NATO rifles, which combine elements of the Swiss SIG SG 550 rifle with the AR-15, offered U.S. shooters a chance to own a rifle patterned much like the revered original Swiss design. In addition, the company also offers a line of highly regarded, long-range precision rifles based on proven Blaser and Sauer designs, further enhancing the company’s credentials as a top-tier rifle manufacturer.

The overall thrust of the offerings from the company, however, was arguably still somewhat Eurocentric. It was obvious SIG Sauer made an intelligent move to build on the strengths the international company could bring to bear through its subsidiaries. But, there proved to be a latent interest in tapping into a design more firmly rooted here in the United States: the AR-15 series of rifles.

A desire to cater more directly to the AR-15 market actually makes a great deal of sense considering the nature of SIG Sauer. The company’s practices present an unusual case study of modern business. While many companies in this country are actively outsourcing work to the rest of the world, SIG Sauer is actually bringing it into the country.

During the past four years, the SIG Sauer facility in Exeter, N.H., has grown by leaps and bounds, adding employees, machinery and manufacturing space. And this growth has gone hand-in-hand with the company’s expansion beyond its traditional niche with handguns and into rifles.

A large part of SIG Sauer’s business revolves around military and law enforcement contracts for its successful handgun designs. Nonetheless, the company recognized a strong desire for package deals with many of these customers. Often, when agencies contracted with SIG Sauer for handguns, they also showed interest in buying rifles.

“We have been very successful with the SIG556 platform in this respect,” SIG Sauer President and Chief Executive Officer Ron Cohen said recently. “However, we recognized that the AR-15/M16 family of rifles was clearly the dominant design around the world.” Many law enforcement agencies have a lengthy background with the AR design, Cohen explained, and SIG Sauer recognized that there was a strong interest for an improved version of the platform. The answer is the new semi-automatic SIG516 series of .223 Rem./5.56x45 mm NATO rifles.

A Better Mousetrap?
“The SIG516 not only gave us a chance to tap into this broad market, but it also offered SIG Sauer a chance to bring its own unique approach to firearm design and manufacture to this popular platform,” Cohen said. “It allowed us to take an established design and make it more robust and hardy while improving on its weak points.”

So what exactly does the new SIG516 series bring to the table? Despite the AR’s broad-based acceptance and its many positive attributes, the company recognized that the basic platform could use some attention in regards to its reliability in harsh environments. Although the standard AR can be a pleasure to shoot because of its excellent ergonomics and extremely good accuracy, its direct-impingement gas system is a point of contention for many. As a result, the SIG516 dispenses with the direct-impingement system and incorporates a proprietary gas-piston operating system designed to offer sound, reliable operation in even the most severe environments.


Shortly before my arrival in New Hampshire, SIG Sauer’s defense program manager, Robert Hirt, ran one of the 14½"-barreled prototypes through a 20,000-round torture test. The rifle ran without cleaning and only periodic oiling, and there was only a single failure to feed. Hirt and I fired the rifle at the SIG Sauer Academy ranges with a variety of 5.56x45 mm NATO/.223 Rem. ammunition ranging from light to heavyweight loadings, including frangible ammunition. A 30-round magazine was loaded with a mixture of all these, and then Hirt ripped off a 30-round shot string without a single malfunction.

To further demonstrate the rifle’s reliability, the same rifle was run through environmental torture tests. It was loaded and placed on “safe” and then dragged through sand. After the gun was inundated with sand, and after ensuring the bore was clear, Hirt once again loaded and fired a full magazine without a single hiccup. The final test was the most impressive—and don’t try this at home. A shallow trench was dug and the rifle buried in a bath of mud with the consistency ofwet concrete. After remaining there for a minute or so, Hirt pulled out the rifle and, after checking for bore obstructions, chambered a round and fired until the rifle ran dry. Once again, not a single malfunction.

Driving Change
Once the rifle was cleaned in a barrel of water, we headed back to the company’s headquarters to take a close, detailed look at the test rifle as well as a 16"-barreled SIG516 Patrol version. “Although the SIG516 brings a lot of improvements to the table, the gas-piston system is the most significant of them,” Hirt told me. He explained in detail how a standard direct-impingement system drives not only carbon and fouling into the action, but also excessive heat; the result is a system in which oil quickly evaporates, and lubrication is necessary to keep an AR running reliably.

The SIG516’s push-rod gas system is designed to reduce this effect by isolating heat and fouling forward of the action and above the barrel, keeping the critical action and chamber area of the rifle clean and cool. In addition, any excess gas in the self-cleaning system is vented out and downward in the forward portion of the handguard just to the rear of the rifle’s gas block through two vent holes in the piston rod.

The SIG516 features a three-position gas regulator located within the Picatinny rail-topped gas block. Sporting a round, grooved knob, the regulator has three markings: a small white dot, a larger white dot and a small red dot. The regulator is locked into position by a spring-loaded plunger on the forward face of the gas block and can be adjusted without tools. A prominent white line on the upper right side of the block aligns with the dots and offers a visual cue to the gas system’s setting.

The small white dot setting is for “standard” or normal operation, allowing enough gas to be tapped from the bore through the gas block to operate the rifle under normal conditions. The larger white dot setting is for “adverse” conditions and allows more gas through the system. The red dot setting is designed for use with a suppressor and minimizes the amount of gas allowed through the gas block.

The SIG516 will also be available with an optional fourth setting designed to completely cut off the gas system, making the rifle, in effect, a single-shot requiring manual cycling.


1   2    NEXT >>

Share |



Enter your comments below, they will appear within 24 hours

Your Name

Your Email

Your Comment

7 Responses to SIG Sauer's SIG516: Expect the Unexpected

Randall Horn wrote:
February 18, 2014

Poorly conceived. I am a fan of Sig, but this rifle does not function as advertised. Not only do I question the article at this point I question the comments as well. I have not seen one of these rifles that did not jam and require an armor level breakdown to repair. Very dissappointed.

Michael wrote:
October 10, 2013

@Jade You have to turn the gas nob into the upright position. There are 3 circles. Make sure yours is on the 2nd biggest circle. You should be fine after that. Read the manual if you are still confused.

Jade wrote:
September 02, 2013

My brand new Sig 516 have a major issue.It doesn't cycle the round,like using a bolt action rifle. You have to full the charging handle every round. Look like SIG SAUER need to improve the SIG 516 little bit more.So disappointed now I have to return this shit back. Now have to send it back to manufacturer. :-(

David M wrote:
December 21, 2011

Without Magazine and Sling - 7.78 pounds for M16A1 Sig516 is 7.6 lbs. its just that you are stronger now.

Joe H. wrote:
November 04, 2011

I purchased my SIG 516 a couple months ago, also in Ca. I went out and shot a few hundred rounds about (4) weeks ago, I would have shot a few hundred more, but it was way too hot outside that day. I shot both .223 and 5.56 all Federal brand, both shot extremely well, nice grouping from about 100-150 feet away. I have to say that the 5.56 ammo is a bit hotter than the .223 I was extremely pleased with rifle, NO jamming, easy do dis-assemble and clean as well. This is not my first SIG, and it won't be my last! GOT SIG?

Rich wrote:
September 14, 2011

Just bought a SIG516, California version unfortunately. U Know, 10 round mag,special mag release, but otherwise a sweet rifle,easy to clean,easy to shoot. Sitting on 2000 rounds of .223 for my next trip to the range. WAY lighter than original M16 we had to use in 'Nam. Now I just need a scope to dial in and I'll be ready for anything.

christian wrote:
June 25, 2011

i have sig 516 can i use metal or only brass ammo,??and should put oil in push rod and the spring