HorseSoldier
New member
I don't think that the instability during full auto fire was due to the caliber as much as it was due to the fact that the rifle had a traditional shaped stock. There is an inadvertently built in pivot point on the rifle stock on the back side of the grip area. This pivot point facilitates muzzle climb in full auto. This is one reason Stoner designed the AR in a straight-line configuration. Obviously the recoil of the 7.62 compounded the problem, but that stock would've made the rifle a bit "helter-skelter" even with a smaller cartridge in FA.
The rifle designed by Earl Harvey (T25, later T47), which was originally preferred over what would become the M14 by the US Army (until the FAL outperformed both, but that's another story . . .) featured an inline stock and a compensator to improve performance when firing automatic. The powers that be watered down his design (more conventional stock design) before dropping it entirely.
Looking at the history of rifle R&D at the time, the M14's only real merits seem to have been that it was (allegedly) easy to produce because of commonality with the Garand (which proved not to be the case in an impressively costly way) and, of course, that it was all American and not some funny foreign weapon like the FAL or EM2.