[Hawk45]

I know the '10' in the double circle is the manufacturing code, but what is the single diget number on the bottom of the other side? Year of manufacture? If so, what years? For instance I have some with 1's, 2's, and a 4.

Thanks in advance.

 

[Mike_F]

I believe it is the mold number that is used to identify the individual molds that the plastic is injected into to make the mags.

 

[WarBaby]

I believe it is the mold number that is used to identify the individual molds that the plastic is injected into to make the mags.

Correct.