The .400 Legend, also called 400 LGND (10x42mmRB), is a SAAMI-standardized straight-walled intermediate rifle cartridge developed by Winchester Repeating Arms.

.400 Legend also addresses a rapidly growing market segment known as "straight-wall-cartridge-compliant" deer-hunting states.

A growing number of states that previously restricted deer hunting to limited-range slug guns or muzzleloading firearms are now allowing rifles chambered in straight-walled centerfire cartridges.

Ohio's Deer Hunting Regulations allow the use of a straight-walled rifle cartridge with a minimum caliber of .357 inches (9.1 mm).

When hunting on private land, virtually all centerfire cartridges with a bullet diameter of at least .243 in (6.2 mm) are legal.