Ron Guth: The first versions of the Shield Nickel included rays on the reverse, between the stars surrounding the large 5 at the center of the coin. These extra elements caused the coinage dies to fail early because of the extra pressure needed to strike the nickel alloy and to force the metal into the recesses of the dies. To correct this problem, mint officials ordered the removal of the rays in mid-1867, creating two varieties: With Rays and No Rays. Striking problems persisted, resulting in a series of coins noted for inconsistent strikes and lots of die cracks.
None of the dates in the Shield Nickel series is particularly rare, although the Proof-only 1877 and 1878 can be elusive and command a nice premium. The low mintage 1880 Nickel is always a favorite with collectors, no matter the grade.
Proofs of most "Without Rays" dates are readily available. Oftentimes, discerning between prooflike circulation strikes and true proofs can be problematic, particularly with the dates in the late 1870s and those from the 1880s.
Interesting varieties include a widely repunched date in 1866, the Open and Close 3's of 1873, 1879/8, and 1883/2.