The SCAR-H, Mk.17 Mod 0 is the heavy version of the Special Operations Forces (SOF) Combat Assault Rifle, made by FN Herstal (FNH) for the United States Special Operations Command (SOCOM). It fires a more powerful 7.62x51mm (.308) NATO round as opposed to the intermidate 5.56x45mm (.223) NATO round and has a slightly different look to it than that of the SCAR-L, Mk.16 Mod 0.
Developed for USSOCOM's SCAR program, the Mk.17 is a variant of the highly modular weapon designed to be adaptable to future weapon upgrades thanks to its multiple MIL-STD-1913 mounting rails and a stock that is adjustable for both length-of-pull and cheek weld height. The weapon can easily be configured in mere minutes for CQC, tactical or precision fire thanks to its interchangeable barrels. It also is ideal as a PDW (Personal Defense Weapon) due to its compact size and design. Some users dislike the Mk.16 and Mk.17 because of the placement of its reciprocating cocking handle, which can (painfully) interfere with the shooter's support hand, depending on grip preference.
By 2014, the SCAR-H, Mk.17 Mod 0 CQB (Close Quarters Battle) variant was the standard-issue assault rifle for most Outer Heaven PMC soldiers. "Naked" versions of the guns were also sold by the gun launderer Drebin 893, of which at least two were kept inside his Stryker.
Behind the scenes
The Mk.17 is a usable weapon in Metal Gear Solid 4: Guns of the Patriots. The model featured appears to be the CQC variant of the second-generation model, as evidenced by the design of the safety/fire selector and the shape of the stock compared to the first- or current third-gen versions. It features four accessory attachment points, adding to its flexibility in battle. It fires 7.62mmx51mm NATO rounds from a straight 20-round box magazine. One can be found for free at the militia safe house along with a GSR pistol. It can be customized with a red-dot optic, 4x ACOG scope, flashlight, lasersight, and foregrips A&B. In real life, both the SCAR-H and -L can accept suppressors, as well as underbarrel-mounted grenade launchers and shotguns, as opposed to in Metal Gear Solid 4.
In some Metal Gear Solid 4 trailers that featured PMCs, they were seen with M4 Customs rather than SCAR-H rifles. In the demo version of Metal Gear Solid 4, the Mk.17 was always locked by ID, now known as "ID Locked."