The Beretta ARX100 is a semi-automatic only variant of the ARX160 intended for the civilian market. It features a Picatinny rail on the top of the receiver for mounting various optics, on both sides of the hand guard for mounting various accessories and on the bottom of the handguard for mounting various grips, a quick change barrel, a barrel length of 16 inch, a folding back-up iron sights, ambidextrous fire/safety selector, magazine release, bolt release and charging handle, a case ejector that can eject the empty brass either to the right side or left side by pressing on the case ejection selector with a tip of a 5.56×45mm NATO (.223 Remington) cartridge, and a telescopic folding buttstock that is also adjustable for length of pull