The 5.7x28mm is a small-caliber, high-velocity handgun and personal-defense cartridge developed by FN. Known for very light recoil, high magazine capacity, and a flat trajectory, it pairs distinctive ballistics with low felt recoil in the pistols and carbines chambered for it.

The 5.7x28mm was developed by the Belgian manufacturer FN Herstal in the late 20th century, originally for a personal-defense weapon system intended to bridge the gap between pistols and rifles. It uses a small-diameter, high-velocity bullet more reminiscent of a miniature rifle round than a traditional pistol cartridge, which gives it an unusual profile among handgun calibers. Ballistically the 5.7x28mm fires a very light bullet — commonly around 27 to 40 grains — at high velocity for a handgun cartridge, producing a flat trajectory and very low recoil. The light, fast projectile and slim cartridge also allow unusually high magazine capacities in the pistols chambered for it. That combination of minimal recoil and high capacity is the core of its appeal to civilian shooters. For years the cartridge was associated with a limited number of firearms and relatively expensive ammunition, but a wave of new pistols and carbines from multiple manufacturers expanded its civilian footprint and improved availability. It remains a specialized round with a distinctive character rather than a mainstream defensive standard. Today the 5.7x28mm is used for self-defense, target shooting, and recreational use, with a growing selection of pistols and carbines. Its blend of very low recoil, flat trajectory, and high capacity is why it has attracted a dedicated and growing following.

General information about this caliber — not a recommendation for this specific firearm.