The ATI Mil-Sport is an AR-15-pattern semi-automatic pistol built around a forged aluminum receiver and chambered in .300 AAC Blackout. It has an 8.5-inch barrel, a blade brace, an M-Lok handguard, and polymer grips in black. The magazine capacity is 30 rounds. 
 

Key Specifications 

• Brand: ATI 
• Model: Mil-Sport 
• Caliber: .300 AAC Blackout 
• Action: Semi Auto 
• Capacity: 30+1 
• Barrel Length: 8.5 in 
• Color/Finish: Blue/Black 
• Receiver: Forged Aluminum 
   

Detailed Features 

• AR-15-pattern semi-automatic with forged aluminum receiver 
• 8.5-inch barrel with blade brace 
• M-Lok handguard 
• Polymer grips 
• 30-round magazine capacity

Owners of the ATI Mil-Sport in .300 AAC Blackout often cite the compact 8.5-inch barrel and brace configuration as the main appeal. At this size, the .300 Blackout cartridge is seen as a natural match, and owners generally find the suppressor-ready setup practical.

Fit and finish opinions are mixed. The forged aluminum receiver draws approval, but some owners note that ATI components can feel less refined than higher-priced AR-pattern builds at similar configurations. The M-Lok handguard is well received for its accessory mounting flexibility.

Value is a common theme in owner feedback. The Mil-Sport is positioned as an accessible entry into .300 AAC Blackout AR-pattern pistol builds, and buyers who approach it with that expectation tend to be satisfied. Those who compare it directly to more expensive brands often note the difference in parts quality.