Im a 24 year old Marine corps veteran of Iraq and Afghanistan. One of my grandpa's friends was visiting at his house and he was also in the military-during peacetime. Somehow, we ended up on the topic of shooting and comparing military rifles. He said some things that didnt seem quite right to me but given his age and respect for my grandfather I did not dispute his statement's. His biggest statement(and boldest) was that the M-1 was a better weapon than the M-14 because it was able to consistently hit at 500 yds. He also said that the max effective range of the M-14 was 300 yds. Now I understand that the M-1 shoots a 30-06 bullet and that the M-14 shoots a 7.62x 51 which roughly translates to .308 . I suppose my question is whether or not this guy is full of it.
I know that the times that I actually "qualed" with the M-16 that I didnt "make my money" at the 500 yd line. Id probably hit an average 5 out of 10 shots there and its hard to hit the shilouette at 500 using open sights. Which brings up a series of questions.

1) Did the military in general "qual" at the 500 in the late 1950's?

2) Did they still "qual" with the M-1 in the late 1950's?

3) Is the max effective range of the M-14 really 300 yds(I think i know the answer): Better question: Is that what the military was "teaching" back then?

This is directed more at the veterans of that era, but all comments are welcome. Im not asking to prove this guy wrong I just want to make sure that im not wrong for questioning his information, albeit to myself.

He is full of pooh. M-14 and M1A1 rifles were staples, and to some extent still are, at 6oo yd. matches.