.223 Remington vs .300 Remington Ultra Magnum
A to-scale size comparison of the .223 Remington and the .300 Remington Ultra Magnum, drawn from SAAMI and C.I.P. cartridge dimensions and aligned at the case head.
.223 Remington (left) beside .300 Remington Ultra Magnum (right), shown at the same scale.
The .223 Remington has an overall length of about 2.26″ with a 0.225″ bullet. The .300 Remington Ultra Magnum runs about 3.60″ on a 0.309″ bullet. That makes the .300 Remington Ultra Magnum about 1.6x the overall length of the .223 Remington. See the full reference for each: .223 Remington and .300 Remington Ultra Magnum.