The 7mm Remington Magnum (also known as the 7mm Rem Mag) is a popular cartridge for hunting and long-range shooting. It was introduced in 1962 by Remington Arms Company and quickly gained popularity among hunters and shooters for its flat trajectory, high velocity, and long-range accuracy. The 7mm Rem Mag bullet has a diameter of 7.2mm and a length of 71.12mm. It is a bottlenecked cartridge, meaning that the neck of the cartridge is narrower than the base, which allows for a higher pressure and a faster muzzle velocity.

The 7mm Rem Mag bullet is capable of traveling at a velocity of around 3,000 feet per second (fps) and has a maximum effective range of around 1,000 yards. It is commonly used for hunting big game such as elk, moose, and bear, as well as for long-range shooting competitions. The bullet is available in a variety of weights ranging from 139 to 180 grains, and can be used in a variety of rifles including bolt-action, semi-automatic, and single-shot rifles. Overall, the 7mm Rem Mag bullet is a versatile cartridge that offers hunters and shooters excellent long-range performance and accuracy.