Zenith Firearms has attempted to offer the best of both worlds—a traditional roller-delayed blowback operating system in a firearm with the latest 21st century features with its Modern Roller-Delayed System (MRDS). This Zenith ZF-56 rifle is part of the company’s newly introduced Modern Roller-Delayed System (MRDS) line of firearms. At first glance, MRDS firearms look distinctively “Modern Sporting Rifle.” Both upper and lower are machined from billet aluminum alloy. The pistol-caliber MRDS firearms are scheduled to be released at SHOT Show 2026 and their MSRP has not been announced. By introducing its Modern Roller-Delayed System, Zenith Firearms is offering all the timeless benefits of the roller-delayed blowback system without having to compromise on the features that modern shooters expect.