Speer TMJ Handgun bullets are engineered to provide the cleanest shooting experience possible for target and competitive marksmen. Unlike traditional Full Metal Jacket (FMJ) bullets, which leave the lead core exposed at the base and allow lead vaporization under high pressure, the TMJ line uses Uni-Cor technology to bond a seamless copper jacket around the entire projectile. This ensures that no lead is exposed to the propellant gases, making it the premier choice for indoor range use where air quality is a concern. Each bullet is swaged twice to ensure a perfectly uniform heel and a consistent .355 diameter, resulting in the match-grade precision and reliable feeding required for high-volume training in 9mm platforms. Defensive Application Non-expanding TMJ bullets carry a high over-penetration risk and do not create large wound channels. They are not recommended for personal defense.