300 Blackout

Selecting the correct ammo for your AR-15 firearm. Why does it matter? 

For 300 Blackout, a 1:7 twist rate is generally recommended for a good balance between stabilizing both supersonic and subsonic projectiles, while a 1:8 twist is more suited for heavier, subsonic bullets. 

Here’s a more detailed breakdown:
    • 1:7 Twist:

      This twist rate is a good compromise for a variety of 300 Blackout applications, including both supersonic and subsonic loads. 

    • 1:8 Twist:

      While 1:8 twist can handle supersonic rounds, it’s often considered the optimal choice for heavier, subsonic projectiles. 

  • 1:5 Twist:

    Some users prefer 1:5 twist for maximizing the performance of heavier subsonic bullets, especially in shorter barrels. 

  • Barrel Length:

    Shorter barrels (8-10 inches) tend to benefit from a 1:5 or 1:7 twist rate, while longer barrels (10.5 inches and up) can often get away with a 1:8 twist. 

  • Supersonic vs. Subsonic:

    If you primarily plan to shoot supersonic ammo, a 1:8 twist is generally sufficient. However, if you plan to shoot a mix of supersonic and subsonic rounds, or primarily subsonic rounds, a 1:7 twist is a good choice. 

In summary:
  • 1:7 twist: Good for a mix of supersonic and subsonic, or primarily subsonic loads. 
  • 1:8 twist: Good for primarily supersonic loads or heavier subsonic projectiles. 
  • 1:5 twist: Can be beneficial for maximizing performance of heavier subsonic bullets in shorter barrels.