SEAL Recon Rifle

The SEAL Recon Rifle (nicknamed the "Sniper M4" and "Recce" ) is an American designated marksman rifle and assault rifle used by the United States Navy SEALs. Essentially a heavily modified M16 rifle, it is intended to provide SEAL snipers and designated marksmen with a versatile, accurate, lightweight, and relatively compact weapon chambered in 5.56×45mm NATO.

History
The concept of an accurized rifle based on the 5.56 NATO cartridge was first observed in 1993 during the Battle of Mogadishu. This led to the development of various options for improving accuracy in the field, including improved ammunition and triggers, a range of optics, free-floating handguards, and rail systems.

Developed in-house by SEAL team armorers, the rifle was centered less around a rigid specification and more around the concept of an accurized rifle that could share the duties and ammunition of fielded M4 carbines, whilst also being able to engage targets beyond the carbines' range.

When further development was handed over to Naval Surface Warfare Center Crane Division, the United States Army incorporated their own concepts and funding into the joint program, resulting in the Mk 12 Special Purpose Rifle which many SEALs were disappointed with.

Former SEAL sniper Kyle Defoor recounts:

"It went to 18' quite frankly because the big Army got involved. Most of us that have a lot of time on one (myself included) think that 16' is better for a number of reasons: [...] The MK12 is ok as it comes, but, me and majority of the guys that were around me immediately [replaced] the fixed stock. Some would go with a Geissele trigger too, and some would put a tube rail back on. All of these little touches were done in house at the shooters home team."
 * 1) 2' does make a difference, especially with a &#91;suppressor&#93;.
 * 2) Weight (it's not pounds at this stage it's ounces) and remember that balance has a factor here too.
 * 3) I've shot both together on the same range at the same time. I don't really care what charts and scientists say, me and [my fellow SEALs] can hit just as good with 16' as 18'.

The rifle is used by the Navy SEALs, US Army Special Forces and Delta Force.

Specifications
Initially, SEAL Recon Rifles were built in-house with the only requirements being a 16" barrel (406mm), and the ability to shoot any 5.56×45mm cartridge in inventory, including the first iterations of the 77-grain (5 gram) Mk262 Mod0 cartridge. Otherwise, the rifle was individualized to the tastes of the user by the armorer or the SEAL themselves.

The stainless-steel barrels were sourced from Lilja Precision Rifle Barrels with a 1:8 (203mm) twist and a unique heavy profile, beginning at 0.980 inches (25mm) in diameter for the first 2.60 inches (66mm) of length, then narrowing down to 0.850 inches (22mm) in diameter, 0.750 inches (19mm) in diameter underneath the front sight block, and 0.725 inches (18mm) in diameter to the muzzle.

These barrels were mated to flat-top upper receivers featuring an M1913 rail, to which optics and back-up iron sights could be attached. Operators commonly chose to install back-up iron sights manufactured by Knight's Armament Company, ARMS Inc, and Troy Industries with the rifles.

Recon rifles were reportedly fitted with free-float handguards, the most popular being the KAC M4 Match RAS and a longer-length LaRue free-float handguard, either of which provides plentiful rail space to mount accessories. KAC free-floated rails (P/N 20214) were part of the Mk12 Mod 1 package and were in common use during the war on terror.

Barrels were sometimes fitted with Ops Inc. 12th model suppressors and their accompanying muzzle brakes.