My records show 6.5TCU with 14inch contender barrel not only was my IHMSA Unlimited gun, but also took several antelope in the Farson area of Wyoming. Didn't have a Chrony then, so can only say 250 yards really stretched its killing capacity on antelope. I never lost one, but 2nd shots were frequently required at the extended ranges. Under 100 yards, it was devistating! I was using open sights with max charges behind 100gr Hornadys and 120gr Sierras. My vote would go to the 6.5JDJ because I always wanted one 'back then'. I don't own a contender now, so it's not a temptation anymore. I think the 6.5JDJ would have enough higher capacity to drive the 120s and even the 140s to a more effective velocity and better killing capacity, especially for game larger than antelope.