This is a very rare example of a post-WWI Springfield Armory prototype semi-automatic rifle. This rifle was manufactured at the same time that John Pedersen and John Garand were developing and experimenting with their early 1921/22 test rifles and it appears to be an alternate redesign using a standard Model 1903 rifle converted into a primer-initiated semiautomatic type rifle. This design was probably developed internally by Springfield Army as an alternate so they could use up the thousands of standard Springfield Model 1903 bolt action that were sitting in storage after World War I, much like the same logic as the post-Civil War conversions of percussion rifled muskets to allin conversions. Clearly they were intending this not to entail a significant modification to the receiver but instead it consisted or a simple kit produced in-house by SA that would be attached to the rear and right side of the 1903 receiver and barrel. This modification included the removal of the standard bolt handle and then with the installation of a new round rear housing on the rear of the receiver and right side. This new housing was attached by two screws on the right side of the receiver ring and probably by the rear trigger guard screw. This new housing totally encloses the rear of the receiver and also includes the modification of the extractor by lengthening it slightly so that the rear of the bolt could slide back into this housing. The bolt still cycled and rotated in a normal fashion using the standard front locking lugs during firing, however firing was initiated by a single fixed pin that would telescope inside the front section of the bolt. During firing this front section would slide reward to unlock the bolt so that the entire bolt would retract inside the new rear housing section and allow a fired cartridge to be extracted. The right side of the receiver also now has a square housing that held an internal, sliding operating rod. The rear end of the operating rod was attached to the side of the bolt (where the bolt handle was removed) and the front section was mounted on the right side of the barrel via a small circular ring mount. The operating rod has a small folding cocking handle, positioned towards the front of the operating rod (just behind the lower barrel band). The standard 1903 rear sight base had been removed from the barrel and now mounted on top of the new enclosed rear section of the action. The trigger guard assembly was also slightly modified as the front section of the magazine box was removed, widened and reattached so that the rifle could be fitted with a 20 round detachable box magazine similar to a BAR magazine. The trigger was still positioned in the same area as originally designed, albeit somewhat too far forward for normal use. It was fitted with a redesigned/modified 1903 style stock and handguard. It still retains its original full length, same as a 1903 rifle and it used the same upper barrel bands. The stock and handguard are now both wider on the right side to house/enclose the operating rod and return spring. The rear section of the stock is identical to the standard 1903 rifle and it is fitted with the 1903 buttplate. The receiver ring still retains the original Springfield Armory markings over serial number "1224743". It also retains its original Springfield barrel that is marked on the expose upper end with "SA-3-21". The design is certainly unique with probably only a handful (at best) ever actually manufactured, as this design was rejected and a completely new action was designed by John Garand in-lieu of using the old 1903 action.

Exceptionality fine with 85% plus of the original parkerized finish overall with only very minor edge and surface rust on the barrel and front sight. The side of the magazine body show most of the wear just from handling and inserting it into the rifle during test demonstrations. The stock and handguard are both in very fine with a nice, matching dark brown walnut color with only a couple handling marks. The left side of the stock does show one minor small stress crack in the cutout slot. Certainly a very unique and very early experiential U.S. prototype rifle design.