Dimpled Bolt Question ?

[Brett248Vista]

Hardness testing marks are pressed in dimples (I've used a Rockwell harndness test machine before) these marks are more like a center point drill mark.

 

[joeface]

DUA with 2 dimples and blue springs

 

[rakusi]

DTM, silver springs and two dimples here.

 

[ceg54]

DTX

mine has two dimples also
got blue springs after it came back from S&W
the pic of the two dimples they look a lot bigger than mine
mine are very small.