Maxim Defense Industries 9mm Roller Delayed System CQB – AR-15 Upper Conversion

The Maxim Defense Industries 9mm Roller Delayed System CQB converts AR-15 lower receivers to 9mm operation using a roller-delayed blowback system. This upper assembly reduces felt recoil and cyclic rate compared to direct blowback 9mm AR systems while maintaining compatibility with standard AR-15 fire control groups. The CQB configuration offers a compact barrel length optimized for close-quarters applications and home defense.

The roller-delayed mechanism uses a two-piece bolt with steel rollers that delay rearward travel, resulting in softer impulse and reduced carrier velocity. The upper is machined from 7075-T6 aluminum with a Type III hard anodized finish. Installation requires no permanent modifications to your AR-15 lower—simply remove the existing upper and attach this complete assembly. Professional installation recommended for shooters unfamiliar with AR-15 platform assembly. System requires 9mm magazines compatible with Glock pattern or Colt pattern (verify included magazine well adapter).

• Part Type: Complete Upper Receiver Assembly
• Compatible Firearms: AR-15 Lower Receivers
• Caliber: 9mm Luger
• Operating System: Roller-Delayed Blowback
• Material: 7075-T6 Aluminum (Upper), Steel (Bolt Components)
• Finish: Type III Hard Anodized
• Installation: Drop-In (No Gunsmithing Required)
• Includes: Complete Upper Assembly, Charging Handle, Bolt Carrier Group