Q. David Bowers (edited and updated by Mike Sherman): In 1873, the authorized weight of the quarter dollar was slightly raised from 96 to 96.45 grains, the latter figure equaling 6.25 grams. To signify the new standard, arrows were added to the date of quarters produced later in 1873 and all those produced in 1874. After 1874, the weight remained the same, but the arrows were no longer used.
This arrows type is scarcer than the earlier 1853-55 arrows type due to much lower original mintages: just over 2.2 million vs. just shy of 34 million of the earlier type. The 1873-CC with arrows is rare, though not as rare as the no arrows type of the same date.
-- Reprinted with permission from "United States Coins by Design Types - An Action Guide for the Collector and Investor" by Q. David Bowers