Indian Head gold pieces was modified by Barber, was "worthy of J.J. Audubon". Dies for the half eagle were sent to the mints in Denver and San Francisco; both western mints reported difficulties in striking the new pieces. Landis wrote to his counterparts at the other mints, advising them that the planchets, or blanks, needed to be shaved very slightly to strike properly. The new coins proved to be thinner than earlier coins of their denomination, due to the field being raised above the design. This meant that automated sorting machines could not reliably sort them when mixed with earlier coins. The new gold
Eisenhower dollar proof planchets were to be used for uncirculated "blue Ikes", but these were placed in the bin for rejected copper-nickel proof planchets, intended to be shipped to be coined for circulation at Denver. The 1977 pieces resulted from pieces rejected for Bicentennial silver proof use, which were again placed in the wrong bin (they should have been melted, as the Mint was no longer striking silver uncirculated Eisenhower dollars). Between 10 and 20 of each date are known. Wexler, Crawford, and Flynn report an even rarer 1776–1976-D dollar in silver, but state that none have been offered at auction or