Not sure about the different case capacity between a Creed and the 6.5x55, but my 6.5x55 loved those Hornady 160 gr. RN's with RL-22 behind them. Very accurate but back then ( about 20 years ago) I wasn't happy with the velocity. The most accurate dosage of RL-22 was only yielding an average of 2366 FPS. Nowadays, as an older, wiser, rifle looney, I look at stuff like sectional density and read things about that bullet weight & velocity from 6.5x55's, 6.5x54's etc. Lots of glowing reports on the effectiveness on game of that combo even without blazing speeds. Now I'm starting to reconsider that load for the good portion of my deer hunting in areas where I can't even see a deer much past 100-125 yds. Still have a couple boxes of those bullets kicking around. If I owned a 6.5 Creed I'd give 'em a try and make a decision based on accuracy & velocity results.