The Remington XP-100 (from eXperimental Pistol number 100) is a bolt action pistol produced by Remington Arms from 1963 to 1998. The XP-100 was one of the first handguns designed for long range shooting, and introduced the .221 Remington Fireball (often called .221 Fireball), which is still the fastest handgun cartridge ever produced by a major ammunition maker. The XP-100 was noted for its accuracy and is still competitive today in the sport of handgun varminting, which it helped create.