What is the difference between a partial collar and misaligned die?

Partial collar strike will have a larger hammer die side, and will have a lip that extends outward from the edge of the coin on that side. Ever heard of a "railroad rim" coin? That's a partial collar strike. Imagine a coin struck sitting part-way in and part-way out of the retaining collar and hit it with a die at 50,000 pounds of force. The metal not retained by the collar would ooze outward causing a partial broadstrike. In major cases this can look quite dramatic, but I have seen a number of minor ones on which you could feel a flange of metal sticking straight out from the rim on the hammer side (usually the obverse).

A misaligned die is a full-collar strike from a die that is tilted in one direction or the other in the press. The edge of the coin would be intact and normal, but the hammer side (again, usually the obverse) would show a doubled rim in the area of the misalignment. These are quite common since they are the same size, shape and weight of a normal coin, thus make it all the way through the machines at the mint and into bags and rolls quite easily. The partial collar strikes are actually larger on one side than they should be, and the more severe ones usually get caught and destroyed.

Misalinged die!!