RIFLE: ATAC DEFENSE MODEL ADBR RIFLE, SERIAL NUMBER BR01074, BLUE / CCH, YES - INCLUDES ORIGINAL BOX, SEMI - AUTOMATIC, 5.56 NATO, 16.5" Notes: Atac Defense ADBR 5.56 Rifle W/ Hard Case. The ATAC Defense ADBR is the ATAC Defense Basic Rifle, an AR-15-pattern semi-automatic rifle. ATAC describes it as a "not so basic" rifle because it is built and inspected using the same general quality-control approach as its higher-end ADER. ATAC Defense ADBR 5.56 - overview Caliber: 5.56 NATO Barrel: 16 inches Operating system: Direct-impingement AR-15 system Configuration: Aluminum upper/lower receiver set Purpose: General-purpose AR-15-style rifle Alternative caliber: The ADBR was also offered in .300 AAC Blackout. Manufacturer: ATAC Defense, based in Lucedale, Mississippi. ATAC's published information indicates that the ADBR uses hand-selected, hand-fit, finished and inspected components, rather than being positioned as a bare-bones entry-level AR. One useful distinction: the ADER is ATAC's Enhanced Rifle, while ADBR stands for Basic Rifle. The ADER received more extensive independent coverage, including Guns & Ammo testing. That review described ATAC's rifles as conventional direct-impingement ARs and noted features such as 7075 aluminum receivers and ATAC's proprietary handguard on the enhanced model.