When the HK released the HK416 in the early 2000s, it rapidly became a hit with elite military and police forces worldwide. Driven by a slick marketing campaign and favorable (albeit disputed) test results from the U.S. military, the HK416 represented a “better mousetrap” version of the AR-family of rifles for many users. Though the advantages of the HK416 have become debatable in modern years, with upgrades to traditional AR rifles enhancing their reliability, Sig Sauer, Inc looked to create their answer to the HK416 in the late 2000s. The result, released in 2010, was the SIG 516.While Sig doesn’t like to emphasize the connection, the SIG 516 was conceived in many ways as a direct counterpart to the HK416. According to the late Jim Schatz, a former H&K; employee and H&K; expert, one of the key people involved in the HK416 was the lead on the SIG 516 development team. The name “SIG 516” is likely just a riff on HK416.In the basic layout, the SIG 516 also heavily resembles the HK416. Both rifles use a short-stroke tappet system placed above the barrel, which drives back a modified bolt carrier in the upper receiver. This allows the rifles to be easily compatible with most AR lowers without much modification.