Alliant powders are exceedingly difficult to find. There are small amounts of rifle powder here and there on occasion but I haven't seen any Bluedot (or any other Alliant shotgun powder) for a couple years now. I used to use it for all my slug and buckshot loads for 12ga but switched to Hodgdon Longshot (fairly close in burn rate, lots of data available) as I was able to find it (but still sparse).
There are just as many far-fetched rumours as to why Alliant powder is unavailable as there are plausible reasons.
-They're shipping it all to ammunition manufacturers
-The US government bought it all
-A series of fires burned down all their powder factories (even the ones in Europe and Australia apparently)
-They lost their export license
-US wholesalers are refusing to ship to Canada
-Obama signed a secret executive order banning powder sales to civilians
-Aliens
-9/11 was an inside job
-etc.
The official line from them that I read is that demand has never been higher, they are operating 24/7 to try to meet the demand, and hopefully we'll see regular shipments coming into Canada in early 2016.
Issue is that in late 2014 they were saying we should see some by late 2015. Now it's moved to early 2016. Maybe later in 2015 it'll get moved to late 2016?
I've kinda given up on Alliant powders in general and switched all my reloading to Hodgdon/IMR/Win. When it becomes a regular item on store shelves again, I might consider it, but until then I stopped holding my breath for any over a year ago.