Re-barrel

[Cosine26]

Do not forget-the M1903 was a compromise. Originally the US service rifle was issued in two configurations: the carbine for cavalry and the rifle for infantry. The original Krag rifle had a 30 inch barrel and a 22 inch barrel for the carbine. Ordnance decided to issue only one rifle, therefore the M1903 was designed with the 24 inch barrel as a compromise. In the early part of the twentieth century, the bayonet was considered to be the most important part of an infantry mans equipment to be supplemented by the rifle. To compensate for the short M1903 rifle, the ordnance department issued a 16 inch bayonet. Since it was common practice to enter battle with a fixed bayonet, I do not know that the M1903 would be any handier that a M1917, though I believe that the 1917 bayonet also had a 16 inch blade. Most infantry rifles of the era had 30 inch barrels, the exception being the SMLE (25.2 inches). The GEW 98 in rifle form had a 29 inch barrel. To the French “elan” and the bayonet would turn the tide of battle, hence the three shot magazine on the French rifle and the 31.2 inch barrel.
The battle sight on most WWI rifles were set for about 400 to 500 yards as tactics called for firing with the rifle at these ranges and then closing with the bayonet. Most army generals ignored the Machine Gun to the tragedy of many WWI troops. As late as 1917 the French launched a cavalry charge against German equipped machine gun groups-with predictable results – massacre.
Most US troops were equipped with the M1917 and most of the green US troops (there were only a small number of trained riflemen, Regular army and USMC) had very little experience with bolt action rifles (the lever action Winchester type was the most popular action up until WWI) so learning to operate a cock-on-closing would not have been any thing they would have been uncomfortable with.
FWIW