The STR carbine stock is a drop-in replacement for M4-type carbine stocks. The STR has improved cheek weld and two water resistant battery tubes on a reinforced polymer a-frame design. A shielded operation lever and a friction locking system prevent accidental adjustment and eliminate excessive stock movement. The STR incorporates two sling loops, left and right side QD sling mount locations and a replaceable butt pad. Two water resistant battery tubes that can be accessed by hand in any stock position. Storage tubes hold two CR123A or AA batteries per side.