Magpul CTR Carbine Stock - MIL-SPEC873750001500 The Compact Type Restricted Stock is a drop in replacement buttstock for AR 15 M16 carbines using MIL SPEC receiver extensions. Designed for light, fast action the streamlined A frame profile avoids snagging and shields the release latch to prevent accidental activation. The CTR features a friction lock system that minimizes excessive stock movement for enhanced weapon stability and an ambidextrous QD sling mount that will accept any push