I think you should also consider that they have to check everyone's PAL information before shipping, to make sure their licenses are valid and not suspended - on 600+ rifles/people. I'm sure that doesn't help matters. Not to mention they started selling these on a Friday, so it likely wasn't till Monday that orders were processed at all.
A lot of people are getting their ship notices and their package delivered on the same day, so clearly they're going as fast as they can - and they're much further ahead than it would seem.
I know patience is a virtue, but let's just be thankful that we're even able to buy and own these rifles at all.