Affordability Evolved: SIG Sauer 716i Tread 7.62 NATO

One benefit of any military small-­arms procurement contract is the amount of testing and evaluation the candidates are put through. In the case of SIG Sauer’s 716i Tread, India’s military thoroughly tested each rifle submitted for evaluation. Our ally then wanted the same rifles from the winning manufacturer tested at the factory, and again in India before accepting them. When the initial contract calls for 72,000 rifles, that amounts to a lot of shooting. That is why the 716i Tread is one of the most proven new firearms now available.

Why the low price? Any AR-­10 usually commands an average of $1,000 more than a comparably equipped AR-­15. Economies of scale are part of the reason for their expense. The AR-­15 sells in much higher quantities, so amortizing the tooling and manufacturing costs is easier. The AR-­10 is more expensive because there are fewer sales to recover those expenses, which is why we see fewer introductions than AR-15s.

SIG Sauer developed the rifle for a contract with the Indian military and, now that they’ve delivered the first order, they have the bandwidth to make these rifles for the American market at a lower price than what’s typical. The Smith & Wesson M&P10 Sport is a no-frills base model that starts at $1,109, for example. Rock River Arms’ X-1 rifle starts at $1,770. And Springfield Armory’s Saint Victor has an MSRP of $1,452. The SIG Sauer 716i Tread retails for only $1,429. The tooling has already largely paid for itself, so SIG Sauer is passing those savings from India’s contract on to America.p

While this rifle may be the best value in an AR-­10 available, it is fully ­featured. The 716i Tread has a 16-­inch, 1:10-inch-­twist barrel with a nitride finish and a rifle-­length gas system. The handguard measures 15 inches long and uses the M-­Lok attachment system. The upper and lower forged receivers are significantly improved versus standard receiver sets, and the bolt carrier group shows engineering improvements.

Putting a 16-­inch barrel on an AR-­10 means muzzle velocity will be low, but portability is great. More interesting than the barrel length is SIG Sauer’s decision to use a rifle-­length gas system on a relatively short barrel for a .308. Longer gas systems are almost always preferred because they delay the bolt’s unlocking and allow chamber pressures to drop. The sooner an AR bolt unlocks, the more violent the unlocking, and the harder it is on the bolt and extractor. Lengthening the gas system delays unlocking and leads to longer bolt and extractor life.

The historical problem with a rifle-­length gas systems on a 16-­inch barrel is that it puts the gas port close to the muzzle. The gas system doesn’t pressurize until the bullet travels far enough down the bore that it passes the gas port. Once the bullet exits the muzzle, pressure in the bore drops to zero. The rifle needs enough distance between the gas port and the muzzle to provide the pressurized gas system enough time to reliably cycle the bolt. This usually means a mid-­length gas system is about the longest that will work on a 16-­inch barrel.

SIG Sauer’s thorough testing of the 716i Tread showed that they could use the longer and milder rifle-­length system reliably if they lightened the bolt carrier’s mass. Inspection of the Tread’s bolt carrier showed lightening cuts on both sides of the carrier and around the rear circumference. This reduces the bolt carrier group weight from the traditional 19 ounces to 17 ounces. Lowering the reciprocating mass inside the receiver and combining that with the longer gas system makes the 716i Tread one of the most comfortable 16-­inch AR-­10s we’ve ever shot.

The receivers are forgings that also have several improvements in the design. The lower receiver has an integral triggerguard and a flared magazine well. A triggerguard such as this is one of the best improvements to a lower receiver. It makes the rifle more comfortable to shoot because it eliminates hot spots from forming on the shooter’s firing hand. SIG Sauer also expended effort on making the 716i Tread ambidextrous. The ambidextrous safety is common enough these days, but the ambidextrous magazine release is not. The magazine release has a fence molded around it on each side, preventing accidental activation, too, and the location of each release is ideal for manipulation with the trigger finger of either hand. Between the fence on the receiver, and the paddle shape, this magazine release design is perfect for a defensive rifle because dropping a magazine will be fast and intuitive, yet it still requires deliberate effort.

Finally, the lower receiver has two integral sling swivel flush cups molded into the rear of the receiver, near the buffer tube. This allows the shooter to attach a single-­point sling on either side.

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The upper receiver is also unique in that it flares out at the front of the receiver where the barrel attaches. Reinforcing this part of the receiver is a good idea because it can endure stress, depending on the shooting position. Shooting the rifle from the prone off a bipod can induce stress on the upper when one bipod leg is subject to more tension than the other. Thickening the receiver walls where the barrel connects reduces the likelihood of this happening.

SIG Sauer uses a massive steel barrel nut to attach the barrel, and the nut works as a heat sink when firing the rifle. However, long strings of fire can still get the assembly hot enough that holding the handguard becomes uncomfortable. Engineers also integrated an anti-­rotation tab that protrudes from the handguard into the upper receiver to ensure that the optic rail remains straight between the upper receiver and top of the handguard.

Time at the range indicated that the 716i Tread hovers right around 1 MOA as it ships from the factory. The rifle would shoot better groups if the adjustable Magpul stock had a bigger toe and had more contact with a rear bag. And it would benefit from a trigger with lighter let-­off.

G&A’s rifle weighed 8 pounds, 1 ounce, according to our scale, and had a single-stage trigger that measured 7 pounds, 10 ounces. When the trigger pull’s weight nears the rifle’s weight, shooting small groups is going to be problematic. The good news is that the aftermarket is awash with excellent triggers. If small groups are your thing, almost any AR-­15 trigger will work in the 716i Tread.

The 716i Tread is one of the best-valued AR-­10s on the market for under $2,000. Who would have thought that an Indian military contract could result in such a well-proven platform at an affordable price?

SIG Sauer’s design also evolves the .30-caliber gas gun. It’s a credit to the company’s engineers who took the time to lengthen the gas system and reduce the bolt carrier’s weight properly to produce a soft-recoiling rendition of the 8-­pound AR-­10. 

SIG Sauer 716i Tread 7.62 NATO

• Type: Direct impengement semiautomatic
• Caliber: 7.62 NATO (.308 Win.)
• Capacity: 20 rds.
• Barrel: 16 in.; 1.10 in. twist
• Overall Length: 34.25 in. (collapsed), 37.5 in. (extended)
• Weight: 8lbs., 1 oz. (tested)
• Stock: Adjustable, six position
• Grip: SIG Sauer polymer
• Length of pull: 11.75 in. (collapsed); 15 in. (extended)
• Finish: Anodized (aliminum)
• Sights: None
• Trigger: 7 lbs., 10 oz.; single stage
• Safety: Two-position selector
• MSRP: $1,429
• Manufacturer: SIG Sauer, 603-610-3000, sigsauer.com