GM Geschoss-Manufaktur Load Data & Reloading Guide

Many GM bullets are designed with driving bands to reduce the amount of bearing surface that contacts the barrel. Instead of the full shank engaging the rifling, only the raised bands make direct contact. This design helps lower friction during bullet travel while maintaining reliable guidance and stability. Driving bands also create additional space for displaced barrel material, which can contribute to more consistent engraving as the bullet enters the rifling.

Driving bands reduce the bullet’s bearing surface, which generally lowers friction between the bullet and the barrel compared to a solid shank of the same length. Reduced friction can contribute to more consistent chamber pressures and may help limit barrel fouling. However, load data should never be interchanged based on bullet design alone. Even with driving bands, reloaders should always use published load data for the specific GM bullet whenever available and work up loads safely.

GM bullets are CNC-machined from solid copper rather than being formed through traditional jacket-and-core manufacturing processes. CNC machining allows for very tight manufacturing tolerances, resulting in highly consistent bullet dimensions, weight and geometry from one bullet to the next. This level of consistency can contribute to reliable ballistic performance, repeatable load development and excellent accuracy. It also enables GM to produce complex features, such as precisely machined driving bands and expansion cavities, with a high degree of precision.