This model has a factory-installed folding stock, flash suppressor and bayonet lug. Designed and sold by Ruger to law enforcement agencies. A number have come on the civilian market through surplus sales and police trade-ins. With the assault rifle hysteria, prices of this model have fluctuated wildly in some areas. Now that Ruger has discontinued the folding stock and high-capacity magazines, this could become even less predictable. Note that this is a semi-automatic and totally different than the full-auto version of this weapon available only through Class 3 dealers.