I can't argue or defend the want of two rounds in an 8 vs 10 debate as bigger is obviously better, although I will say that the SVT and the K43 weren't available in 1941, while the M1 was. Using the criteria of just the detachable box, the BAR was superior to all three- double the capacity, with a detachable box
the BAR was superior however it was used as a light machine gun/fire support role, not as a battle rifle and just the fact that it was fully automatic puts it in a separate class altogether from the rest of rifles discussed.
as for the discussions of M1 not being widely fielded, um...yes it was. the marine corps used the 1903 up until guadalcanal and once they started pilfering Army supply stores and got their hands on a number of M1s there was an overwhelming demand for them. by the end of the war in the pacific a staggering amount of marines were using M1s. in europe and africa however, where our troops were not fighting a jungle war, the army was able to get away with issuing the longer springfields, BARs and other weapons that were not suitable in the pacific theatre.