UTG Pro RBUS1BM Mil-Spec OPS Ready S1 Stock Kit Black Synthetic 6 Position for AR-15, M16

The UTG Pro RBUS1BM is a mil-spec OPS Ready S1 6-position stock kit built for AR-15 and M16 platform rifles that demand durability and reliability. If you're running a tactical rifle, patrol gun, or home-defense AR, this collapsible stock gives you the adjustability to dial in your setup whether you're in plate carrier, light jacket, or shirt sleeves. The six positions let you find the length of pull that works for your build, your shooting style, and your gear configuration.

Built from high-impact polymer, this stock handles the wear and tear of hard use without breaking the bank. The rubberized recoil pad absorbs impact and stays put when you're working through rounds or transitions. Quick Detach sling attachment points—including a reversible QD socket and ambidextrous sling loop—mean you can set up your rifle for whatever mission you have in mind, whether that's range time, hunting, or home security. Tight tolerances on the mil-spec buffer tube keep everything locked down solid with zero rattle.

The S1 kit comes complete: extension tube, buffer, buffer spring, tear-drop ring, and castle nut are all in the box. Black synthetic construction shrugs off weather and abuse, and the chamfered edges and slanted cheek rest add comfort during extended shooting sessions. This is honest-to-goodness mil-spec gear that doesn't pretend to be gucci—just solid, dependable performance for the shooter who values function over flash.

Key Features

• Six-position collapsible design for customizable length of pull
• High-impact polymer construction resists weather and abuse
• Mil-spec buffer tube with rolled threads for secure, rattle-free fit
• Thick rubberized recoil pad for impact absorption and durability
• Reversible QD sling swivel housing and ambidextrous sling loop for flexible carry setup
• Chamfered edges and slanted cheek rest for shooting comfort
• Black synthetic finish

Specifications

Frequently Asked Questions

What comes in the UTG Pro S1 stock kit?

The kit includes the 6-position collapsible stock, extension tube, buffer, buffer spring, tear-drop ring, and castle nut—everything you need for installation on a mil-spec receiver.

Is this stock compatible with my AR-15?

Yes. The UTG Pro S1 is designed for AR-15 and M16 platform rifles with mil-spec receivers and buffer tubes.

How many length-of-pull positions does it have?

The S1 offers six adjustable positions, letting you customize the stock length to fit your shooting style, body armor, or gear setup.

Does it come with sling attachment options?

Yes. The stock features a reversible QD sling swivel housing and an ambidextrous sling loop attachment, giving you flexibility in how you mount your sling.