this coin appears to be in AU condition and the edge is wider on the obverse side. Could this be some type of collar error? Maybe the collar was loose. Can anyone comment please?
Although both reeds are there, the copper side of edge is significantly thicker. They are not level. Maybe a slight partial collar error. Railroad rim?
It is not unusual for a slightly dull punch to pull the copper and/or clad layers further over the edge of the coin. This coin appears to be an expression of such. A railroad rim on a reeded coin will show a portion of the edge without reeds which this coin does not show. The first photo in this article shows an example. http://www.error-ref.com/inverted-dioe-installation/ This is a photo of a Railroad Rim on a non reeded coin.
Is that the case always? Isn't the collar what holds the edge and rim in place? If so, how can the edge be uneven even though both reeds are present if not for a collar error?
I am not sure what you mean by "both reeds are present"? The reeding is impressed on the coin edge by the collar. If the collar or planchet are not set properly, then the collar will only impact a portion of the edge, leaving the reeding on the edge incomplete. I do not see incomplete reeding on the coin in the OP which indicates that the collar and planchet were in their standard positions. Here is a photo of a collar die in place:
If collar is in place how can it. spill over the edge? Is it a loose collar? Never seen anything like this. Is there a link or pics of a coin that has this type of edge? Can you or anyone show me a coin or link that confirms your assessment? Respectfully thanks!
The first photo in the link I provided above shows that, I believe. http://www.error-ref.com/?s=inverted+die
It is reeded - look at the link I provided on inverted dies, please. (I have posted the link twice above). In this case, because the reeding is near the obverse face, it becomes diagnostic of an inverted die strike.
