The UTG Pro RBUS3BM Mil-Spec OPS Ready S3 6-Position Stock Kit is a complete drop-in replacement system built for AR-15 and M16 platforms. This is a no-frills, purpose-built stock assembly that delivers the adjustability and durability serious shooters and builders expect without unnecessary complexity or premium pricing. Whether you're assembling a new rifle, upgrading an existing build, or need a reliable stock for duty, training, or the range, the RBUS3BM gives you the core components in one kit.

Made in the USA, the stock body is molded from impact-resistant polymer engineered for real-world abuse, while the extension tube is precision-machined from aircraft-grade aluminum with rolled threads and anodized finish—both choices that resist corrosion and wear. The 6-position adjustability lets you dial in length of pull to match your frame, gear, or shooting style. Six positions means you're not locked into one setup, and the stock maintains a compact, lightweight profile that won't bog down your rifle or create snag points on gear. The integrated rubberized butt pad and slanted cheek rest work together to anchor the rifle into your shoulder and promote consistent control under fire or on the bench.

The kit arrives complete: stock, mil-spec extension tube, buffer, buffer spring, teardrop ring, and castle nut—everything you need to install. Ambidextrous sling loops and a QD swivel housing accommodate both left- and right-handed shooters, and the design incorporates fully dehorned corners and smooth contours so it won't snag gear or clothing during transitions. This is kit-level component quality that respects both your budget and your rifle's potential.