.400 Cor-Bon Load Data

The .400 Cor-Bon is an automatic pistol cartridge developed by Cor-Bon Ammunition in the United States in 1997. It was designed by Peter Pi to mimic the ballistics of the 10 mm Auto while using a .45 ACP–based platform. To achieve this, the cartridge takes a .45 ACP case and necks it down to .40 caliber (≈10 mm) with a 25° shoulder, creating a bottleneck design that improves feeding and can handle a variety of bullet shapes more reliably than straight-walled cases.

Performance of the .400 Cor-Bon places it between .40 S&W and 10 mm Auto ballistics, offering higher velocity and a flatter trajectory compared to standard .45 ACP. Factory loads with 135–165-grain bullets typically achieve around 1,250–1,400 ft/s, delivering effective energy suitable for self-defense, practical shooting, and even handgun hunting at short range.

One of the cartridge’s notable features is that in many pistols chambered for .45 ACP, only a barrel swap is needed for conversion to .400 Cor-Bon, with no change to magazines or other parts in many designs like the 1911. It’s sometimes referred to as the “poor man’s 10 mm,” offering similar performance without the heavier recoil or higher pressures of true 10 mm loads.