This is an excellent example of a late 1950s production, experimental M1 Garand rifle chambered in the experimental duplex cartridge of "22-06". After WWII, the U.S. Army developed a series of experimental cartridges that were intended to improve the hit probability by using hyper-velocity and multiple projectile cartridges based on the .30-06 cartridge. The test rifles used at that time were the standard service rifles of the day: the M1 Garand. This rifle is one of those test rifles intended to use/fire a duplex cartridge. The duplex .22-06 cartridge itself is actually a .30-06 case necked down to .22 caliber that had an elongated neck which held two 50 grains bullets (stacked on top of each other). The intent being that a multiple projectile cartridge would increase your hit probability just like firing a salvo cartridge. The rifle itself was manufactured by Springfield Armory in 1957, and it has the original and correct all corresponding parts. The barrel, as noted, is in .22 caliber, and it is marked on the side: "SA 37999 5 57 8142 4233 RP CAL 22 06 DUPLEX". The bolt is marked "SA 65282871-SA/YO2", and the operating rod is marked "6535382 SA". The complete trigger group is all correct late post-war SA production and is correctly marked. It is fitted with the standard gas cylinder with a high hump gas cylinder lock and a four-slot gas plug marked "NHC". It is fitted with a standard front and rear sight set and a standard walnut stock and hand guard set. The stock has the DOD cartouche on the left side and a single circled "P" proof in the pistol grip area.

Excellent plus with 99% of the original parkerized finish overall showing only minor finish wear on the left side receiver rail and top front edge of the bolt lugs where the action was cycling a few times. The bolt face looks unfired. The stock and handguards are all in excellent condition showing only minor handling marks and a nice matching dark colored oil finish overall. Mechanically excellent. An exceptional example of an exceptionally rare experimental M1 Rifle!