This is the ammunition that is preferred by many law enforcement professionals world wide, and with good reason. The HST hollow point is engineered to pass through the toughest barriers without plugging and still retains nearly 100 percent of its weight. This bullet design has a deeply tapered jacketed hollow point profile with internal and external skiving to ensure optimal penetration and reliable expansion. It features a unique cannelure that mechanically locks the copper jacket to the heavy lead core for maximum weight retention. This means consistent reliable expansion with deeper penetration which provides more energy on target without over penetrating. HST has demonstrated and proven superior performance in the FBI test protocols used by law enforcement when selecting duty ammunition. If you take your personal safety and self defense seriously, then you're carrying Federal Premium Personal Defense HST.