I found this after a quick search and it says the pic you have is a wooden mock up of a Bullpup by Springfield Armory. Also it listed a lil bit of history
Article by D.E. Watters
In September 1948, the U.S. Army's General Staff creates the civilian Operations Research Office (ORO) to supply the Army with scientific advice on conducting operations in an age of nuclear weapons. The ORO's research mandate quickly spread out to conventional weapons, especially when the U.S. entered the Korean 'police action' in 1950. One of the first projects for the "Infantry" division of the ORO was Project ALCLAD: the development of improved body armor. The head of the division, Norman A. Hitchman, reasoned that in order to improve body armor, one had to know how wounds were created and where they were received. A mathematical analysis of three million casualty reports from both World Wars was entered into the ORO's computers, along with on-the-spot analysis from ORO staffers in Korea. To Colonel René R. Studler, US Army Ordnance's Chief of Small Arms Research and Development, this sounds as though the ORO is infringing on his turf. Between his distrust of ORO's civilians and the increasing pressure applied by the British for adoption of a mid-range cartridge, Studler attempts to buttress his position supporting a 'full-power' cartridge. Studler requests that the Aberdeen Proving Grounds' Ballistics Research Laboratory (BRL) prepare its own report on the effectiveness of the infantry combat rifle.
Both reports were finished in 1952, and the conclusions of each overlapped. In March, Donald L. Hall of BRL published "An Effectiveness Study of the Infantry Rifle." The crux of the study was that a smaller caliber could give terminal performance equal or greater to that of a larger bore. Moreover, a smaller bore weapon might have superior hit probabilities at shorter ranges. Combined with the additional cartridges carried per unit weight, a soldier carrying the smaller caliber weapon could inflict more casualties upon the enemy than another soldier with a larger caliber weapon.
In June, the ORO published Hitchman's report "Operational Requirements for an Infantry Hand Weapon." Hitchman found that the majority of combat rifle use did not exceed 300 yards, and that marksmanship was severely degraded by terrain and visibility at ranges beyond 100 yards. In fact, the chance of being struck by a rifle bullet was seen as being nearly as random as being struck by a fragment from a high explosive shell. The time and amount of target exposure had more bearing on whether a target was hit versus marksmanship skills. Given such, an infantry weapon designed to provide controllable "pattern-dispersion" within a 300 yd range might be preferable to a weapon that provides precise single shots at longer distances. Furthermore, at the shorter ranges, a smaller caliber weapon might give acceptable "wounding effects" and allow for controllable "salvo or volley automatic" fire. The key to effectiveness is control; an uncontrollable automatic weapon is seen to be no more advantageous than a semi-auto counterpart. Hitchman projected that a four round salvo with a predictable 20" spread might provide double the hit probability at 300 yards over a single shot fired from a M1 rifle. A lighter, smaller caliber cartridge would have the side benefit of allowing enough ammunition to be carried for an equivalent number of fired salvos to the individual cartridge capacity of the current rifle.
The concept of controlled "volley/burst" fire led to the creation of the multi-agency Project SALVO in November 1952. The ORO's favored platform was a single barrel weapon using duplex or triplex loads (2 or 3 bullets in one case). Springfield Armory and Winchester created multi-barreled weapons. BRL stayed with a rather conventional entry: a modified M2 Carbine firing a .224" caliber cartridge.