I am going to start documenting US 50 cent mint mark location differences

US 50 cent 1976 D
D closer to end of neck D farther from end of neck

Only a 4 or 5 mm difference. Easy way to tell. Look at dot between 1776- 1976.

1971 D
D closer to bottom of neck far from bottom of neck

1968 D
D closer to bottom tip of neck D further away from bottom tip of neck


Bold D Thin D

Daryl: You have great observation skills and I wish you the best in your collection of Kennedy Halves mint mark variants.
Check this site out - it may help you.
http://coinauctionshelp.com/mintingprocesshistory.html#.WDofsfWcHIU

Mint-made errors
Errors originating in the mint are almost always by accident. However, these types of glitches are usually prized by numismatists because of their rarity. It should be made clear that mint-made error coin are not equivalent to coins that have been damaged after the minting process.
Small errors do occur occasionally, but this doesn’t mean that those coins are completely invaluable or even that they won’t be circulated. Today, some meagerly flawed coins are still released from the mint.
Flawed coins weren’t always prized possessions. This phenomenon didn’t start until around the 1960s in the United States. Despite it’s relatively short history, the collection of quirky coins has maintained its spirited growth and will hopefully continue to thrive.

I wish I could help you more. Ed

Not really errors. Definately varieties. the mm was punched into the die later on the process. Now the mintmark is part of the master, and so you will not find a variety in mm placement.