Best 5.7x28mm Ammo Choosing the best 5.7x28mm ammo starts with understanding the cartridge, the firearm it is designed for, and the differences between available factory loads. Developed by FN Herstal, the 5.7×28mm cartridge is a small-caliber, bottlenecked centerfire round used in select pistols and personal defense weapon-style firearms. Its lightweight projectile design, relatively high velocity, […]