This refers to specific reloading information for the .223 Remington cartridge using Trail Boss powder to achieve subsonic velocities. Subsonic ammunition, by definition, travels slower than the speed of sound. This specialized loading data provides precise measurements of Trail Boss powder to be paired with specific bullet weights for safe and effective subsonic performance in .223 Remington firearms. An example would be a specific charge weight of Trail Boss paired with a heavier .223 bullet, such as a 77-grain projectile.
Reduced velocity loads offer several advantages. Primarily, they significantly decrease muzzle report, making them ideal for shooting in noise-sensitive environments or when using suppressors for maximum noise reduction. Additionally, subsonic loads can exhibit improved accuracy due to reduced recoil and the elimination of transonic instability. The development and refinement of propellants specifically designed for reduced velocity applications, like Trail Boss, have made crafting safe and effective subsonic loads more accessible to handloaders.