Hornady BLACK 5.56 NATO 75gr InterLock HD SBR

The Hornady BLACK 75gr InterLock HD SBR solves a real problem: most 5.56 defensive ammunition is designed to perform at velocities from 16-20 inch barrels. Fire that same ammo from a 10.5-inch SBR and the reduced velocity can cause bullets to fail to expand, turning a defensive hollow point into an expensive FMJ. Hornady engineered this round from the ground up for the 2,321 fps muzzle velocity typical of 11.5-inch barrels, using propellant chemistry that burns efficiently in short gas systems and a bullet designed to expand reliably at lower impact velocities.

The 75-grain InterLock bullet borrows technology from Hornady's proven Critical Duty FlexLock line. The InterLock ring mechanically locks the copper jacket to the lead core, preventing jacket separation on impact. This ensures the bullet holds together through intermediate barriers while still expanding to create effective wound channels. At SBR velocities, the bullet expands to approximately 1.5x its original diameter while retaining over 90% of its weight.

The heavier 75-grain bullet also compensates for the velocity deficit of short barrels by carrying more mass to the target. With a 0.23 G1 ballistic coefficient, it remains effective inside 200 yards, which covers the realistic engagement envelope for any SBR or AR pistol. The brass cases are reloadable with Boxer primers, and the propellant is tuned to minimize flash signature from short barrels, a critical consideration for home defense scenarios where preserving night vision matters.