The SG551 is the carbine version of the SG550 with a 16-inch barrel, sharing the same folding stock, proprietary translucent stacking magazines, and piston-driven action. Even fewer SG551s were imported to the US than SG550s before the 1989 import ban. The SG551 was used by Swiss special operations forces and select European police units. Examples in the US civilian market command extraordinary prices. Type: Rifle Action: Semi-Automatic Caliber: 5.56x45mm NATO Capacity: 30 Year introduced: 1988, Switzerland Weight: 128 oz Overall length: 35.4" Status: Discontinued Military use: Yes Intended use: military, law_enforcement, collector