The Hornady Black Rifle Ammo 5.56 NATO 75 gr InterLock HD SBR Black is built for short-barrel rifles in the InterLock HD SBR series and delivers purpose-driven performance for 10.5"-11.5" barrels whether suppressed or unsuppressed, offering shooters a dramatically reduced sound signature and virtually no flash or residue to keep suppressors from fouling or overheating during extended strings of fire. With a 75 grain InterLock Heavy Duty bullet, brass casing, 5.56x45mm NATO chambering, 2321 fps muzzle velocity and 897 ft-lbs of muzzle energy, this load maintains uniform velocity and accuracy to provide a controllable rate of fire in automatic platforms while meeting the FBI protocol for barrier and terminal performance, making it suitable for close-quarters duty, tactical training, and hunting applications where reliable expansion and penetration matter. Because the InterLock HD SBR Black uses propellant technology tuned to short barrels, shooters will notice reduced muzzle flash and residue compared with standard 5.56 loads, improving follow-up shots and suppressor life; as a United States origin product shipped in a 20-round pack, it caters to range days, duty carry setups, and hunters who run compact AR-style rifles.