7.62x51 Blank Qustions

Below are a number of blanks that I’m trying to figure out why they are slightly different to the standard model of blanks.

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Canadian Blanks

  • DA 58 (Standard blank for comparison)
  • DA 58
  • DA 66

American Blanks
L C 6 9 (Standard blank for comparison)

  • WCC 62
    L C 6 9 (purple lacquer on the rose crimp), seems to be the ‘M82A1’

Dose anyone know why these blanks are different from the ‘standard versions’?