The “grain” in reference to ammunition describes the weight of the projectile, specifically the bullet, measured in grains (gr). A grain is a unit of mass equal to 1/7000 of a pound avoirdupois. As an example, a 9mm bullet might weigh 115 grains, while a .45 caliber bullet could weigh 230 grains. This weight directly influences the bullet’s momentum and, subsequently, its energy and trajectory.
The weight of the projectile is a critical factor in determining its effectiveness. A heavier projectile, all other factors being equal, will typically deliver more energy upon impact, potentially resulting in greater stopping power. The selection of a projectile weight depends on the intended use, such as target shooting, hunting, or self-defense, each requiring different levels of energy and penetration. Historically, the measurement using this unit of weight provided a standardized method to compare and categorize the potential performance of different projectiles.
