Rs Reg Full-length Modular Lower

The RS Regulate Reg Full-length Modular Lower is a precision mounting component designed for AK-platform rifles equipped with side-rail optic mounts. This full-length lower receiver extension functions as the foundation of RS Regulate's modular AK-300 System, enabling shooters to pair standardized upper receiver blocks with a compatible lower base for repeatable, zero-holding optic mounting on Eastern European AK variants. The modular architecture eliminates the need for multiple complete mount systems, allowing operators to standardize their optic platform across similar platform rifles.

Weighing just 0.31 pounds with compact dimensions of 3.25 × 1.25 × 7.55 inches, the full-length lower distributes load evenly along the side rail and maintains a neutral mounting position ideal for conventional optic placement and mounting accessories. The full-length design provides superior rail surface coverage compared to front-biased or rear-biased alternatives, offering flexibility in upper block positioning and accessory placement. The modular connection system allows field-swappable upper blocks without disturbing zero, a critical advantage for training, duty rotation, or multi-mission rifle configurations.

This component is engineered for shooters operating AK rifles with non-Yugo, non-Czech, and non-proprietary side rails—specifically most Eastern European AK models with standard side-rail geometry. Users who rely on modular mounting systems, run multiple optic configurations, or require a stable mid-length mounting platform benefit from the full-length lower's balanced design. It integrates seamlessly with RS Regulate's full catalog of uppers and accessories, making it essential for operators standardizing their AK optics ecosystem.

RS Regulate's AK-300 system represents a mature solution developed over more than a decade, addressing the need for repeatable, zero-holding optic mounts on side-rail AKs. The full-length lower is one of nine lower variants in the lineup, each tailored to specific rifle platforms and rail configurations, ensuring that shooters can select the optimal mounting geometry for their exact rifle model and intended optic placement.