Usually, the mintage for a coin struck at the Philadelphia Mint is larger than that of similar-dated coins struck at the subsidiary, or branch, Mints. However, that is not always the case because sometimes the Philadelphia Mint is distracted by other projects. Such was the case in 1850. With large amounts of gold coming in from California, the Philadelphia Mint focused on producing the new $20 gold piece, the new-ish Gold Dollar, and the Quarter Eagle. In that environment, Mint employees at Philadelphia struck only 227,000 Half Dollars -- a record low for that denomination since 1815.
As might be expected, the 1850 Half Dollar is scarce in all grades, rare in Mint State, and extremely rare above MS64. The strike quality of this date is inconsistent. We've seen everything from fully struck examples, those that have weak stars or weak talons and feathers on the reverse, and everything in-between. MS63 to MS64 seem to be the typical grades for this date.