The patent-pending Magpul CTR (Compact/Type Restricted) – Mil-Spec Model is a drop-in replacement butt stock for carbines using mil-spec receiver extension tubes. Designed for light, fast action the streamlined A-frame profile avoids snagging and shields the release latch to prevent accidental activation. The extra-power lock mechanism uses a premium chrome-silicon spring to avert auto-collapse failure and maintains strength by resisting spring relaxation. The CTR also features a supplemental friction lock system that minimizes wobble for enhanced weapon stability and accuracy. The Mil-Spec Model includes a standard 0.30" rubber butt-pad which provides positive shoulder purchase to prevent slippage even with body armor or modular gear.