RS Regulate Yugo Rear Biased Lower Features The RS Regulate Yugo Rear Biased Lower mounts directly to the side rail of Yugo and Serbian type rifles giving shooters a rear biased attachment point that positions an optic for a natural cheek weld and consistent eye relief. Introduced as part of the AK-300 Modular Side Mount System that RS Regulate began rolling out in 2012 this lower is one of nine lower variants engineered to fit the wide range of Eastern European and Yugo pattern side rail receivers. The rear biased design is tailored to the dimensions of OPAP NPAP and M21 pattern rifles so the fit is precise rather than generic. Pairing it with one of RS Regulate s modular uppers completes a mounting system built around consistent return to zero. Machined with a matte black finish the lower resists wear and glare in the field while matching the look of most AK pattern furniture. It is compact measuring under six inches long and weighing just over three ounces so it adds minimal bulk to the rifle. This lower is not compatible with folding stock variants so shooters running a fixed stock Yugo or Serbian rifle are the intended audience. RS Regulate s modular system lets a shooter swap uppers without disturbing the lower s zero making this a practical foundation for a dedicated optics setup on these rifles. RS Regulate Yugo Rear Biased Lower Specifications Manufacturer: RS Regulate Model: Yugo Rear Biased Lower Type: Side Mount Color: Black Finish: Matte Compatible Hosts: Yugo/Serbian Type Rifles (OPAP NPAP M21) Available At: GrabAGun