For the '50s, nothing off the top of my head, although it's really just a synthesis of a bunch of things I've observed and learned over decades:
First is the obvious, that the M14 is a Garand with a detachable box magazine and a much better gas system in the front end, but it still has an op rod and the same exposed bolt on top. Compare to the other major designs of the 50s:
The AR-10 wasn't exactly, except it inspired the AR-15, then there's the FNH FAL and the H&K G3/91: the only exposure the action gets is the necessary ejection port.
And of course the M14 officially won the US competition. The corruption in that should be searchable both directly (e.g. search for "sabotage" of the alternatives, but you'll also find hits alleging sabotage of the M16), and indirectly in the much studied history of the adoption of The Black Rifle, as one of the major books on it is titled. Some of those accounts should detail why the civilians in the DoD took this out of the Army's hands (and I gather terminating with extreme prejudice that unit of the Army, and of course closing down Springfield Armory in 1968; the M60 debacle probably also played a role).
It's also self-evident that something major happened to establish 7.62 NATO. E.g. I just read in Wikipedia that the British were going forward with their own rifle design using their own intermediate .280 British (which looks to be noticeably better than 7.62x39, a bit hotter than 6.8 SPC but probably wouldn't travel as far), then Labour lost the 1951 election...: https://en.wikipedia.org/wiki/FN_FAL
For the '50s, nothing off the top of my head, although it's really just a synthesis of a bunch of things I've observed and learned over decades:
First is the obvious, that the M14 is a Garand with a detachable box magazine and a much better gas system in the front end, but it still has an op rod and the same exposed bolt on top. Compare to the other major designs of the 50s:
The AR-10 wasn't exactly, except it inspired the AR-15, then there's the FNH FAL and the H&K G3/91: the only exposure the action gets is the necessary ejection port.
And of course the M14 officially won the US competition. The corruption in that should be searchable both directly (e.g. search for "sabotage" of the alternatives, but you'll also find hits alleging sabotage of the M16), and indirectly in the much studied history of the adoption of The Black Rifle, as one of the major books on it is titled. Some of those accounts should detail why the civilians in the DoD took this out of the Army's hands (and I gather terminating with extreme prejudice that unit of the Army, and of course closing down Springfield Armory in 1968; the M60 debacle probably also played a role).
It's also self-evident that something major happened to establish 7.62 NATO. E.g. I just read in Wikipedia that the British were going forward with their own rifle design using their own intermediate .280 British (which looks to be noticeably better than 7.62x39, a bit hotter than 6.8 SPC but probably wouldn't travel as far), then Labour lost the 1951 election...: https://en.wikipedia.org/wiki/FN_FAL