Willy, neither AA#5 nor Unique will make true magnum-level loads. They will both make serviceable midrange .357 Mag loads, but for magnum loads, you'll need something slower. AA#9, 2400, H110, etc.
Like I wrote in my initial post... my Universal loads are fun out of a revolver, they hit harder than a .38 Special but they aren't real
serious .357 loads and they don't run the Coonan. I don't imagine loads built with Power Pistol would do really well either.
Good that you got your Unique loads to do it, but switch to something like 2400 and you'll get the full effect of the .357!