How Does Barrel Length Affect Velocity?

Lately I’ve been curious about the performance of my 10.5” AR pistol barrel chambered in 5.56.  Specifically, I wanted to know how far the round could travel while still being considered ballistically-acceptable for personal defense.  Additionally, I wanted to know how much of a difference there was in terms of drop-off at a given distance … Continue reading How Does Barrel Length Affect Velocity?