.243 Ackley Improved vs .300 Remington Ultra Magnum
A to-scale size comparison of the .243 Ackley Improved and the .300 Remington Ultra Magnum, drawn from SAAMI and C.I.P. cartridge dimensions and aligned at the case head.
.243 Ackley Improved (left) beside .300 Remington Ultra Magnum (right), shown at the same scale.
The .243 Ackley Improved has an overall length of about 2.71″ with a 0.243″ bullet. The .300 Remington Ultra Magnum runs about 3.60″ on a 0.309″ bullet. That makes the .300 Remington Ultra Magnum about 1.3x the overall length of the .243 Ackley Improved. See the full reference for each: .243 Ackley Improved and .300 Remington Ultra Magnum.