Early Norma factory ammunition loaded for Weatherby used Hornady RN and FMJ. Norma had been loading these bullets to a velocity of . Norma dropped the velocity of the cartridge to while Hornady introduced the mechanically locked-in lead core InterLock bullets in 1980 to improve the terminal ballistics of their bullets. Subsequently, Hornady introduced the InterBond FMJ (IB-FMJ) and RN (IB-RN) bullets which featured a brass jacket with a welded lead core. The IB-FMJ and IB were loaded by Norma for the Weatherby cartridge. These Hornady .458 caliber round nose and solid bullets were later found to have a performance envelope of not exceeding in the .458 caliber.