The Franklin Armory BFSIII M4 is chambered in 5.56x45mm NATO and built around the Binary Firing System trigger, which gives it both semi-automatic and binary firing modes. At 5.8 lbs with a 16-inch barrel, it handles well in a variety of roles from range work to home defense. 
 

Key Specifications: 

• UPC: 818725012235 
• Caliber: 5.56x45MM NATO 
• Action: Semi-Automatic 
• Capacity: 30 Rounds 
• Barrel Length: 16 inches 
• Weight: 5.8 lbs. 
• Finish: Black 
   

Detailed Features: 

• Installed BFSIII Trigger: The binary trigger fires on both pull and release, effectively doubling your round output per trigger cycle in semi mode. 
   
• 15" FST Handguard: Free-floating design keeps the barrel isolated from grip pressure, which helps maintain consistent accuracy. 
   
• Lightweight Barrel: Reduces carry weight without sacrificing durability. 
   
• A2 Grip & A2 Flash Hider: Standard grip geometry and a flash hider that cuts muzzle signature at the brake. 
   
• Collapsible M4 Stock: Adjusts length of pull for different shooters and shooting positions. 
   
• Optics Ready Design: Flat-top upper accepts any standard optic mount, no adapter needed.

Owners of the Franklin Armory BFSIII M4 Gen III tend to focus on the binary firing system as the rifle's defining characteristic. The ability to fire on both pull and release gets consistently positive reviews for adding a different dynamic to range sessions and competitive shooting. Build quality is generally regarded as solid, and the optics-ready setup is appreciated for how cleanly it accepts aftermarket optics.

The main criticisms center on two things: weight and legal complexity. A handful of users wish it were lighter. More commonly, shooters bring up the jurisdictional restrictions on binary triggers. The BFS system is not legal in all states, and some buyers flag this as something to verify before purchasing. Those concerns aside, the overall reception among people who can legally own and use the binary mode is positive.

Build quality feels excellent, and mine has stayed issue-free through roughly 800 rounds. It initially disliked AAC ammunition but now runs it fine. The binary trigger is tremendous fun, though sustained rapid fire gets the rifle hot enough that a heat guard is worth considering.