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
In the 1990's Delta Force sniper teams 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.
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.
Barrels were sometimes fitted with Ops Inc. 12th model suppressors and their accompanying muzzle brakes.