ORIGINAL: BOWHUNTERCOP
difference between pre 64 versus post 64 is on is push feed (pre 64) , the other is claw type feed (post 64) there maybe some other differences, I should know it since I own a pre-64
The pre 64 was a mauser style controled round feed system and the post 64 was a push feed similar to the remintgon 700 or howa bolts. They also made the M70 classic starting in the early 90s that had the controled round feeding with mauser style claw extractor. The pre 64 and classic are the more disirable but the post 64 are a decent rifle also.