with the SCAR-L (Mk 16) in Afghanistan. The SCAR is manufactured in two main versions: the SCAR-L ("Light") and SCAR-H ("Heavy"). The SCAR-L fires
5.56×45mm NATO rounds from
STANAG (
M16) magazines. The SCAR-H fires the more powerful
7.62×51mm NATO cartridge. Varied barrel lengths are also available for different purposes, such as
close quarters battle or long-range engagements. The initial solicitation indicated that the SCAR-H would also be capable of being chambered in the
7.62×39mm M43 Kalashnikov cartridge, as well as the
6.8×43mm Remington SPC cartridge, however, FN is not currently offering this configuration, and the models have likely been cancelled. The SCAR-L, designated MK 16 by USSOCOM, was intended to replace the
M4A1, the
MK 18 CQBR and the
MK 12 SPR that had been in service (before SOCOM decided to cancel the order for the Mk 16 Mod 0, see below), whereas the MK 17 (SCAR-H) had been intended to replace the
M14 and
MK 11 sniper rifles in use. However, the weapon will only supplement other weapons, while issuance remains of the operator's discretion. The semi-automatic only MK 20 Mod 0 Sniper Support Rifle (SSR) is based on the SCAR-H. It includes a longer receiver, a strengthened barrel extension and barrel profile to reduce whip and improve accuracy, and an enhanced modular trigger that can be configured for single-stage or two-stage operation together with either a folding or a non-folding precision stock. The SCAR has two
receivers: The lower is constructed of polymer, and the upper receiver is one piece and constructed of aluminum. The SCAR features an integral, uninterrupted
Picatinny rail on the top of the aluminium receiver, two removable side rails and a bottom one that can mount any
MIL-STD-1913 compliant accessories. The lower receiver is designed with an
M16 compatible pistol grip, flared
magazine well, and raised area around the magazine and bolt release buttons. The front sight flips down for unobstructed use of optics and accessories. The rifle uses a "
tappet" type of closed gas system much like the
M1 carbine while the bolt carrier otherwise resembles the
Stoner 63 or
Heckler & Koch G36. The SCAR is built at the
FN Manufacturing, LLC plant in Columbia, South Carolina, in the United States. Since 2008, FN Herstal has been offering semi-automatic versions of the SCAR rifles for commercial and law enforcement use. These are dubbed the 16S (Light) and 17S (Heavy), and are manufactured in Herstal, Belgium, and imported by FN Herstal's U.S. subsidiary, FN America of
Fredericksburg, Virginia. FN America slightly modifies the rifles (supplying a U.S. made magazine and machining a pin in the magazine well) to be in compliance with U.S. Code before selling them. The FN SCAR 20S
Precision Rifle was introduced in 2019. It is a
semi-automatic only civilian version of the FN Mk 20 SSR. In 2020 the FN SCAR 20S 6.5CM variant was announced chambered in
6.5mm Creedmoor. This chambering has been selected by USSOCOM for long-range use.
Enhanced Grenade Launcher Module Introduced in 2004 as an addition, the Enhanced Grenade Launching Module (EGLM), officially referred to as the FN40GL, or Mk 13 Mod 0, is a 40 mm grenade launcher based on the GL1 designed for the
F2000. The FN40GL is marketed in both an L (Light) and H (Heavy) model, for fitting the appropriate SCAR variant. The EGLM system features a double-action trigger and a swing-out chamber. These offer two advantages over the
M203 system, the first being that the launcher does not need to be re-cocked if the grenade does not fire, and the latter being that longer grenades can be used. Like the M203, the FN40GL uses the same
High-Low Propulsion System. The FN40GL is deemed a third-generation grenade launcher, meaning it is multifunctional: it can be used mounted to the rifle or as a stand-alone system; it is manufactured using a number of materials like aluminum, composites, and polymers; the breech opens to the side for use of longer
40 mm rounds, including less-than-lethal; and it is mounted on the bottom accessory rail instead of requiring specialized mounting hardware. The FN40GL is attached to SCAR rifles on the bottom rail with a trigger adapter and dual locking clamp levers on the launcher, limiting the ability to integrate with other rifles. Barrel length is , and is unique in that it is the only system where the barrel can swivel to the left or right for loading, while other breech-loading launchers pivot specifically to one side. This enhances its ambidexterity, making it easy for a left-handed operator to load under fire. The standalone stock assembly has the FN40GL mounted to the bottom rail as with the rifle, but still has 3 o'clock, 6 o'clock, and 9 o'clock rail positions for other accessories. This is mainly during non-lethal uses for other mounted additions like
LED lights and
laser dazzlers. The trigger is placed lower than normal for operation with the user's middle finger while keeping their trigger finger free to use the rifle. The double-action trigger is long and heavy to prevent easily and unintentionally firing a round under stress. It can fire the
Pike 40 mm guided munition.
FNAC In July 2007, the
United States Army announced a limited competition between the
M4 carbine, FN SCAR,
HK416, and the previously shelved
HK XM8. Ten examples of each of the four competitors were involved. During the testing, 6,000 rounds apiece were fired from each of the carbines in an "extreme dust environment". The purpose of the shoot-off was to assess future needs, not to select a replacement for the M4. During the test, the SCAR suffered 226 stoppages. Since a percentage of each weapons' stoppages were caused by magazine failures, the FN SCAR,
XM8 and
HK416 performed statistically similarly. The FN SCAR ranked second to the XM8 with 127 stoppages, but with fewer stoppages compared to the
M4 with 882 stoppages and the HK416 with 233. This test was based on two previous systems assessments that were conducted using the
M4 carbine and
M16 rifle at
Aberdeen Proving Ground in 2006 and the summer of 2007 before the third limited competition in the fall of 2007. The 2006 test focused only on the
M4 and
M16. The Summer 2007 test had only the M4 but increased lubrication. Results from the second test resulted in a total of 307 stoppages for the M4 after lubrication was increased, but did not explain why the M4 suffered 882 stoppages with that same level of lubrication in the third test. The SCAR was one of the weapons displayed to
U.S. Army officials during an invitation-only Industry Day on 13 November 2008. The goal of the Industry Day was to review current carbine technology for any situation prior to writing formal requirements for a future replacement for the
M4 carbine. The SCAR was one of the competing weapons in the
Individual Carbine competition which aimed to find a replacement for the
M4 carbine. A variant of the SCAR was entered into the competition, known as the
FNAC (
FN Advanced Carbine). The weapon is similar to the SCAR Mk 16 Mod 0 but with modifications including a weight reduction resulting in a loaded weight of , a bayonet lug for an
M9 bayonet (which the Mk 16 does not have), a rail mounted folding front iron sight instead of the gas block mounted sight, and a non-reciprocating charging handle. The competition was cancelled before a winner was chosen.
HAMR IAR In 2008, a variant of the FN SCAR—the Heat Adaptive Modular Rifle (HAMR)—was one of four finalist rifles for the
Infantry Automatic Rifle (IAR) competition. The IAR was a
United States Marine Corps requirement for a lightweight automatic rifle for squad automatic rifle use. The FN entry was different from existing SCAR versions in that it combined
closed bolt operation (fires from bolt forward/chambered cartridge) with
open bolt operation (fires from bolt to the rear, no chambered cartridge), switching automatically from closed to open bolt as the weapon's barrel heats up during firing. There have been previous firearms with mixed open/closed bolt operation, but the automatic temperature-based operating mode switch is an innovation. The IAR competition was expected to result in Marine Corps procurement of up to 6,500 automatic rifles over five years, but eventually the SCAR variant was passed over in favor of the
Heckler and Koch HK416 rifle, later designated as the
M27. ==Adoption==