.223 Remington vs .243 Ackley Improved
A to-scale size comparison of the .223 Remington and the .243 Ackley Improved, drawn from SAAMI and C.I.P. cartridge dimensions and aligned at the case head.
.223 Remington (left) beside .243 Ackley Improved (right), shown at the same scale.
The .223 Remington has an overall length of about 2.26″ with a 0.225″ bullet. The .243 Ackley Improved runs about 2.71″ on a 0.243″ bullet. That makes the .243 Ackley Improved about 1.2x the overall length of the .223 Remington. See the full reference for each: .223 Remington and .243 Ackley Improved.