1999 P 5 Cent Piece With Doubling On The Back

Yep, just Die Deterioration Doubling.

Keep asking we don't mind when someone is open to learning.

to CCF good luck on future finds and above all have fun.

As long as people are taking advice and learning, this community is very patient with rookies. It's a phenomenal online resource to learn about variety coins, mint errors, and all sorts of treasures. Three years ago, I came here knowing zero about varieties, and now I have a growing collection of truly excellent and valuable coins.

Hands down, this is the best short guide that I've read on how to distinguish Machine Doubling vs. Die Deterioration vs. doubled dies:

Http://www.jimscoins.com/downloads/Strike%20Doubling%20Flyer.pdf

The best long form guides can be found on Error Ref, the Wexler archives, and right here in Dr. Coop's many image slide presentations. Those resources are much more detailed. The best approach is to read J.T. Stanton's flyer on doubling, then look at coins under magnification, and then work through the long form resources with guidance from the fine folks on CCF. You'll be a pro at it in no time.