A longer barrel on this specific firearm platform generally refers to a barrel exceeding the standard 14.5 inches found on the M4, often extending to 16 inches or more. This configuration offers increased muzzle velocity, leading to improved accuracy and effective range. For example, a 16-inch barrel provides higher projectile energy downrange compared to a shorter barrel, contributing to flatter trajectories and potentially greater terminal ballistics.
The enhanced ballistic performance of a longer barrel brings several advantages in various operational contexts. This improved accuracy and effective range are desirable for designated marksmen or those engaging targets at longer distances. Historically, modifications impacting barrel length have been common, reflecting the evolving needs of military and law enforcement personnel. These changes often aim to optimize the weapon system for specific mission requirements.