There should be some ordering. And I just checked, it is not according to the time the answer was given.
What is the ordering?
Answers with the same vote total are put in random order unless there are more than 30 answers, in which case the order is net votes then oldest to newest.
in response to the Fastest Gun in the West "problem" (I say that because I don't think it's a problem at all.
The change caused a problem with questions that had more than one page of answers. See Random sort order results in answers being “lost” as the user changes to a different page:
This has been one of SO's more controversial changes and (imho) not a positive one.
The ordering of answers with the same score is random when ordering by votes: