Gun company's don't seem to be able to get 45 caliber revolver chambers right. My 25-2's were too big 625-2 were too small. Ruger has been the same way.
Anyway, I have a bunch of new auto rim brass and I have played with it for hunting loads and such.
There is no advantage to it for the most part. When hunting it makes it easy to just drop out fired cases and replace them. You don't have to go to another moon clip but thats about the size of it.
Unique has its issues and it may not be the perfect powder for all uses in the 45 acp/auto rim but it ain't bad. I have burned more of it than anything with bullets from as light as 180gr all the way to 300gr