SEAL Recon Rifle

The concept of a 5.56 NATO-based accurized rifle was first seen in 1993 when American troops were deployed in Somalia.[2]

Developed in-house by SEAL team armorers,[4] the rifle's existence 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.[5]

When further development was handed over to Naval Surface Warfare Center Crane Division,[2] the US 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.[6]

Former SEAL Sniper Kyle Defoor recounts:[1]

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:

1. 2" does make a difference, especially with a [suppressor].
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 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 Geisselle 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.

The SEAL Recon Rifle was initially built in-house with the only specifications being the ability to shoot any 5.56×45mm cartridge in inventory (including the first iterations of the 77-grain (5 g) Mk 262 Mod 0 cartridge), and that the rifle have a barrel 16 inches (406 mm) in length.[6] Otherwise, the rifle was individualized to the tastes of each operator.

The barrel blanks have a 1:8 inch (203 mm) twist and are stainless steel[7] with a unique heavy barrel profile, starting with 0.980 inch (25 mm) in diameter for the first 2.60 inches (66 mm) of length, then narrowing down to 0.850 inches (22 mm) in diameter, 0.750 inches (19 mm) in diameter underneath the front sight block, and 0.725 inches (18 mm) in diameter to the muzzle. The barrels have the Ops Inc 12th model suppressors with the specified muzzle brake to mount the suppressor. A rifle-length gas system is used. These barrels were mated to flat-top upper receivers, and back-up iron sights (BUIS) from Knight's Armament Company (KAC).

Recon rifles built by NSWC Crane are reportedly all fitted with a free-float hand-guard system, the most popular being the KAC M4 Match RAS and the LaRue longer-length free-float handguards (which protect the barrel and provide more area to mount tactical accessories). KAC free-floated rails (P/N 20214) were most often used by the time of the Global War on Terror, which was the basis for the Mk 12 mod 1 rifle. Barrels are a mix of stainless Lilja or Douglas and SOCOM heavy profile barrels, the former offers higher accuracy (1 MOA or better) whilst the latter offers as much accuracy, but with better barrel life. Some operators also reportedly use various back-up iron sights by KAC, ARMS Inc, and Troy Industries with the rifles.[7]

A variety of optics and sights can be attached to the receiver.[5]

• Mk 12 Special Purpose Rifle

• SEAL Recon Rifle images and parts-list at CloneRifles.com.