1970 Nickel D Mechanical Doubling ?

to the family!

You got it, MD. recognizable because 1) sharp edged shelving,, 2) the letter/number are not increased in size from normal. Most often doubled digits appear either blatantly 2x or are larger than normal with a softer division, notching at bottom/top ends. Sorry can't post pic examples, on cheap*** tablet at moment.

Keep searching and askin'.

BTW, on reverse, UNUM, left edges is just wornout die and the "doubled" forehead is also MD, but could be what's called master die doubling, meaning this same error is on multiple dies as compared to the single MD caused by high speed machining/loose die.