As others stated, it should be okay to shoot almost any commercial ammo in your rifle...assuming there is nothing wrong with it. If headspace is okay, fire away!

I speculate that you may be asking this question because of the problems with improper heat-treating on the 1903 rifle causing brittle receivers. This is a whole other can of worms, but...if your rifle was made in 1943 it would not be affected by this.

daveboy