mod 51 means that numbers cycle between 0 and 50. For example, 51 mod 51 is 0 because the numbers have completely cycled and have returned to the starting point. 52 mod 51 would be 1, 53 mod 51 would be 2, and so forth.
Made 1960-1974. Value is based on condition, but roughly $275-$350.
The absolute value of 51 is 51.
The value is 51.
1964 mod 101 = 45
1970 - 1987
100 years (approx) sn pa20568
I think it should be 7.62 x 51 mm ...
@1970
999 MOD 1000 = 999
It is possible
Since the mod 37 is a pump gun and the 51 is semi-auto, if it fits then it is a coincidence.
$100