Suppressor-ready concentric 5/8 x 24 threads – Continuous picatinny rail interface between upper receiver and handguard – Extended ambidextrous charging handle with dual claws – Adjustable gas regulator for shooting suppressed and unsuppressed – Ambidextrous safety lever bolt release and magazine release – New HK USA enhanced ergonomic grip – M-LOK interface with integral ambi QD cups – Updated medium contour barrel profile – Ambidextrous QD end plate – Winter trigger guard – Match rifle cold-hammer-forged barrel – Caliber 7.62 x 51mm – Operating principle Gas operated short stroke piston – Bolt system Rotating bolt – Trigger system Two-stage trigger – Magazine capacity 10 / 20 round – Length (overall) 31.4 in / 798 mm – Barrel length 13 in / 330 mm – Height 7.75 in / 197 mm – Weight (empty magazine) 7.95 lb / 3606 g – Barrel thread pitch 5/8 x 24 – Safety Firing pin block trigger latch safety