I am speaking of Fred Bear Kodiak Mags. I follow 1961,62,63 and 64 but they are a puzzle yet .But 1965 5M13 is the lowest and 5M6864 highest.
1966 6M18 is the lowest and 5M8002 highest
1967 7U276 is the lowest and 7U8798 highest
1968 8U35 is the lowest and 8U9518 highest
1969 9U85 is the lowest and 9U16,517 highest
I think you can tell the 1970 ,71 and 72 apart.
1970 1 to 38,275 with long overlays
1971 1 to about 34,000 they did not start over on January 1 so it starts 34,001
1972 34,001 to about 72,246 .
the 71 and 72 are short overlays and option screw.
What do you think of my guess ?