Yes too all of the above.
Nope they all had too meet the same standards, however there are a few makers some guys think there is some magic in.Hmm…Well, then.
RE quality, is there anything to suggest significant differences? Or mostly annecdotal?
SA only made 167000ish, that’s a lot less than TRW’s production.I think it's also a rarity thing. TRW made only 23% of the total number of M14 rifles for the government. Combine that with the level machining quality they had from jet engine production and you get the demand. They were sort of the Knights Armament of their day