Frangible firearm projectiles, firearm cartridges, and methods for forming the same. The projectiles are formed from metal powder and include an anti-sparking agent. One or more of iron, zinc, bismuth, tin, copper, nickel, tungsten, boron, and/or alloys thereof may form the metal powder. The projectiles may be formed from a compacted mixture of two or more different metal powders. The anti-sparking agent may include a borate, such as boric acid, zinc chloride, and/or petrolatum. The anti-sparking agent may be dispersed within, and/or applied as a coating on, the exterior of the projectile. The compacted mixture may be heat treated for a time sufficient to form a plurality of discrete alloy domains within the compacted mixture. Such domains may be formed by a mechanism that includes vapor-phase diffusion bonding and oxidation of the metal powders and that does form a liquid phase of the metal powder or utilize a polymeric binder.