Rock Island Armory 3.10 Double Stack - .45 ACP The Rock Island Armory 3.10 is a compact double-stack .45 ACP pistol that combines the classic 1911 design with a shorter, more compact configuration. It features a rugged all-black appearance, familiar 1911-style controls, and a comfortable grip that gives it a solid feel in the hand. With its compact frame and 3.1" barrel, the 3.10 offers a distinctive take on the traditional 1911 platform. The .45 ACP chambering and double-stack design make this an especially interesting option for anyone looking for a compact 1911-style pistol with a little more capacity than a traditional single-stack design. Caliber: .45 ACP Barrel Length: 3.1" Action: Single Action Style: Double-Stack 1911 Finish: Black A compact .45 ACP with classic 1911 styling and double-stack capacity, the Rock Island Armory 3.10 is a unique addition to any collection.