I run into a deal on a Springfield Model 1903 Mark 1 that I don't know a whole lot about it chambers a 30/06 round and thats what its supposed to be it has an internal mag thats a 4 round but none of my rounds will fit the mag because all of my loads are too long because my loading length is determined by my rifles that they are made for and all are a bit too long but they are all hunting tipped bullets a round nosed bullet would work. other than that I think the barrel was changed as there is no stamp or proof marks on the barrel and I read that this model was made for a Pederson device that is a pistol type thing that attaches to the action to fire semi auto 30 caliber bullets. thats about all I know it has been sporterised and without any barrel markings that is why I think that the barrel has been changed