Ron Guth: Beginning in 1971, all silver was removed from the Half Dollar, in favor of the same copper-nickel clad alloy that had been in use on Dimes and Quarter Dollars since 1965. Mintages remained low relative to all other denominations, with the result that the Half Dollar was seldom used or seen in circulation (a situation that persists today). Though somewhat lengthy, this series is easy and affordable to collect as either circulation strikes, Proofs, or both.
Some dates, such as 1987-P and D, 2001-P, 2002-P and D, and others were not issued for circulation but are available only in Mint sets, adding a bit of a challenge.
Major varieties include a 1974 Doubled Die Obverse and different shaped mintmarks on the 1979 Proof Half Dollars.
This series does not include the Bicentennial coins or the 90% Silver Proofs of 1992 and beyond; these are treated as separate sub-types.