Excuse me, but isn't the Mark I rifle the one with the left side of the receiver milled out to serve as an ejection port for the Pedersen Device?
If your Springfield is indeed a Mark I, please reconsider modifying it. It has collectors value and interest AS IS. The Pedersen Device was a replacement bolt which slipped into place in lieu of the regular 30-06 bolt. A 40 round 30 cal. pistol cartridge magazine was inserted into the replacement bolt and the gun could be fired semiautomatically. Pick up a copy of William Brophy's The Springfield 1903 Rifle or visit the Springfield Armory National Historic Site in Springfield, Mass if you want to see a Pedersen Device. Leave it Mil-Spec and buy yourself a M1903A3 to sporterize. Better yet, buy yourself a beat up Mauser 98 and sporterize that.
------------------
Vigilantibus et non dormientibus jura subveniunt