Ammunition tailored for velocities below the speed of sound involves specific propellant charges and projectile selection to achieve optimal performance without exceeding this threshold. This specialized information, often presented in tabular format, specifies precise measurements of powder type and weight, bullet type and weight, case overall length, and other critical factors, enabling handloaders to assemble cartridges safely and effectively. For example, a combination of a heavy-for-caliber projectile and a reduced powder charge is a common approach.
Crafting cartridges for this specific velocity range offers several advantages, including reduced noise, improved accuracy, and optimized terminal ballistics for certain applications. Historically, suppressed firearms and specific hunting scenarios have driven the demand for such specialized ammunition. Handloading provides a means of tailoring ammunition to meet these precise needs, offering control over variables difficult to achieve with factory-produced rounds. This fine-tuning capability contributes to improved ballistic consistency and potentially reduced cost compared to commercially available subsonic options.