Magnum
A cartridge designation indicating higher velocity, more powder capacity, or both compared to a standard parent cartridge.
The term is informal and “magnum” carries no fixed technical meaning across cartridges. .300 Winchester Magnum is a belted case derived from the .375 H&H; .338 Lapua Magnum is its own unbelted case; .300 PRC is “magnum-class” without the word in its name.
Practical pattern: magnums burn more powder, kick harder, and shorten barrel life faster than standard cartridges. The trade is higher velocity and flatter trajectory at long range.