The 03-A3 rifles were WW2 production and had a lot of stamped parts, as opposed to the machined parts of the earlier Springfield rifles. The 03-A3s were faster and cheaper to produce than the earlier rifles but chintzy in the eyes of the purist.
Many of the 03-A3 rifles also had 2-groove barrels, and the purists wanted 4 grooves.
But, that being said, I've always preferred the bridge-mounted aperture sights of the 03-A3 rifles as opposed to the barrel-mounted sights of the earlier Springfields.
