1966 Kennedy Half non-SMS MS66 PCGS Elusive So Fine! During 1965 and 1966 the Mint was switching from proof sets to the Special Mint Sets and from the 90% silver Kennedys to the 40% silver. The 40% silver 1965–1967 Kennedys in the SMS sets were produced with a modicum of care (if not enough for some of us picky collectors), but the 1965–67 business strikes were being produced alongside the 1964 Kennedy business strikes by the gazillions
The quality suffered as a result.
While a lot of nice 1964 circulation strike Kennedys were saved, the 1965–67 non-SMS coins were little saved at the time, and they are mighty tough issues at the Gem and higher levels, as the PCGS populations demonstrate.
PCGS Population: 57 in 66, 4 finer, including one MS68 “wonder coin” that a friend of ours owns (4/2013).