6 GT vs 6.5 PRC
A to-scale size comparison of the 6 GT and the 6.5 PRC, drawn from SAAMI and C.I.P. cartridge dimensions and aligned at the case head.
6 GT (left) beside 6.5 PRC (right), shown at the same scale.
The 6 GT has an overall length of about 2.64″ with a 0.243″ bullet. The 6.5 PRC runs about 2.96″ on a 0.264″ bullet. That makes the 6.5 PRC about 1.1x the overall length of the 6 GT. See the full reference for each: 6 GT and 6.5 PRC.