Gun Report

Ruger SR-556FB 5.56x45mm NATO 223 Rem.

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Tough call between this and the Stag, which we eventually made on price. We didn't shoot enough to decide if the gas-piston system delivered more reliable operation than the proven impingement design, so we decided on what we saw. This gun shot on par with the Stag, and its sights were much better than both the DIG guns, our testers said. The SR's trigger was heavier, though. We liked the Ruger's rail system and pistol grip better than the others.

Ruger SR-556FB 5.56x45mm NATO 223 Rem.

Gun Details

Model Name
Model Number
Home Defense
Law Enforcement
Caliber Plus Cartridge
Weight Unloaded
Length of Pull
Action Type
Action Finish
Trigger Pull Weight

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The 4-position adjustable regulator can tune the rifle to ammunition.
In the gas-piston system like that used in the Ruger, gases from the barrel vent into the gas block and then against a piston, top, which in turn strikes an operating rod that replaces the gas tube.
The SR-556FB is equipped with Troy Industries Folding BattleSights (thus the FB in the name), which our test team praised. Pushing in a spring-loaded button allows them to be folded down or flipped up. The windage-adjustable rear sight includes 2 apertures, and the protected HK-style front sight is elevation adjustable.
The Ruger's Troy quad-rail gave the SR-556 plenty of room for flashlights, lasers, bayonets, whatever strikes the shooter's fancy. We counted 50 inches of mounting surface on the sides and top of the gun.

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