5.7 x 28mm

Keltec

Keltec R50 5.7x28mm Semi-Auto Rifle with Folding Stock and Threaded Barrel

Diamondback

Diamondback 5.7x28mm Semi-Auto Rifle with 8-Inch Threaded Barrel and OD Green Picatinny Rail

Keltec

Keltec SUB-2000 Gen 3 Rifle in 5.7x28mm with Collapsible Stock and 20-Round Magazine

Keltec

Keltec SUB-2000 Gen 3 5.7x28mm Rifle with Folding Stock in Olive Drab Green

Keltec

Keltec SUB-2000 Gen 3 Rifle in Tan with 20-Round Magazine