I never found it necessary to mill/drill out the dimples/crimp indentations that hold the spacer. On mine a follower would freely slide up & down the empty magazine body with nothing done to them after removing the spacer.
Running a flat mill file along the inside corner of the magazine will minimize any obstructions found & give you piece of mind though.
All of my spacers easily popped out with a flat tip screwdriver.
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The magazine's vertical indentations, for holding the top round in the 4013 mags, is problematic & need to be minimized for the 10mm Auto round to feed smoothly out of the mag as they contact the shell's body, rather than at the extractor groove once the spacer has been removed.
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I have details about the white 10mm's follower modification in my thread too.
Thread:
Genesis: 4013 to 1013 to 1016
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