Model 1901. The Model 1903 Springfield had its origins in experimental models based on the Mauser rifles encountered in the Spanish American War of 1898. Trials in 1901 seemed very successful, and Springfield believed that the Model 1901 rifle would be approved for manufacture. They unofficially begin production of some parts. Unfortunately, the Ordnance Department decided changes were needed, and the parts being made had to be scrapped. Occasionally these will be encountered assembled into complete M1903 style rifles, but as they were never heat-treated, they would be very dangerous to fire.  An unfinished receiver and bolt from the Model 1901 rifle, which closely resemble the Model 1903.  The "safety lug" on the bolt is a bit lower, and that the rear "bridge" of the receiver lacks the raised step found on the 1903 rifles. The left wall of the receiver has a deep cut for thumb clearance when loading with stripper clips, and a longer reinforcement on the side. The 1901 parts turn up from time to time, but are only  viewed as collectibles.