I love the oddball old school calibers more than the next guy but I would feel like I betrayed my country chambering it in 6.5x55 or the 7x57. alittle too euro for the red white and blue springfield. seems like you want a light recoiling med to long range caliber. I would do the 25-06. it would take advantage of the fullsized receiver on the 1903. if you like the euro stuff try the 257 roberts Ackley improved 40 degree shoulder. (257 Roberts is based on the 7x57 case).