1947 Nickel. "7" Variety.

Possibly. I have seen the 9s and find the "transition" to be more gradual also more prone to that cause because of it's location (much lower). The transition between the "tail" and what looks like the bottom of the number 7 is very pronounced. Even more some with the naked eye.

I would like to see the whole coin, but I think based on what I see I would guess die damage. I dont see any coin roller marks in that pic...

So going through about 150 47 nickels I found 4 that exhibit a similar pattern (albeit not as pronounced). Here is another. If it would be a failing die, this one would be earlier in the process. Picture doesn't quite capture it but placement and angle very close. What's interesting that I have not found a single ML example that exhibits anything similar. All that said, I wouldn't rule out Ningcumpoop's...rolling theory.