M77 bolt

[308longdistance]

When, SN or date, did the M77 bolt change from blue to stainless?

 

[chet15]

When, SN or date, did the M77 bolt change from blue to stainless?

If I remember correctly, the stainless bolt began when the M77 Mark II series began.
Chet15

 

[308longdistance]

Thank you.