Sub-X (Subsonic - expanding) bullets are meticulously crafted to deliver substantial impact while minimizing noise. These bullets are tailored for deep penetration, operating below the speed of sound and are constructed with a lead core. The design includes long grooves in the gilding metal jacket, which, along with a flat profile and the patented Flex tip insert in the bullet's hollow point cavity, ensures dependable expansion even at low velocities. The patented Flex Tip technology facilitates expansion at subsonic velocities, specifically at speeds as low as 900 feet per second (fps) Verified efficacy - complies with FBI standards for terminal ballistic testing protocols, ensuring optimal performance and reliability Optimized case crimp - the lead core bullet, featuring a cannelured jacket, ensures a secure and reliable case crimp, enhancing performance in semiautomatic firearms Versatile firearm compatibility - engineered for optimal fit, feeding and functionality across diverse firearm platforms, including those with gas-operated systems