1985-D 1985-P Dimes "For example, a poorly-struck perimeter is pervasive among 1985-D Roosevelt dimes. It appears to stem from a combination of inadequate upset and excessive die convexity (primarily on the obverse die)." http://www.coinworld.com/news/us-coins/2015/02/collectors--clearinghouse--legitimate-error-or-altered-coin-.all.html# And another view: Ken Potter: “I would argue that the 1985-P dime is an error. It appears to have been struck from one of a number of improperly heat treated obverse dies. The improper heat treating caused die sinking; manifested most prominently as flattening and excessive concavity near the rims of the coins. This effect is seen on many 1985 dimes from both Denver and Philadelphia Mints (with all the dies being made in Philadelphia during that era). The reverses of these coins are most often weakly struck from well-worn dies, the weakness due to poor fit-up of the dies caused by the defective obverse dies and die wear; the effect seemingly progressive. The areas of greatest flattening on the obverses shift around the circumference of the coins (sometimes showing strongly in more than one area) suggesting uneven heat treating from the dies involved.”
