While the Colt 1911 was chambered in the powerful .45 ACP cartridge, the externally similar Colt Ace was chambered for the far less powerful .22 LR cartridge. Accordingly, military, police, or civilian shooters could shoot the Ace without the recoil and expense of the 1911, but with similar ergonomics and sight picture. Except for the earliest models, the barrels of these guns are constructed with a hinged floating rear chamber that amplifies the recoil, cycling the heavy slide.