Suggest you look at Alliant's web site for data. All my manuals are getting some age on them but they at least used to list loads with 7/8 oz of shot using Bullseye as low as 4500 psi & with one oz in the mid 6500 range.
Unique does not truly come into its own in the 12ga until you reach at least a 3De-1 1/8 oz load. By careful selection of the other components pressures can be in the low 7K's to about 8K. Personally I think that Alliant has very wisely refrained from recommending a powder as slow as Unique with very light charges at very low pressures. While some other companies have done so many problems can arise from such use. Personally when I have gun which i want to keep the pressure low for I generally also desire to keep the load light for protection of old wood etc. for this I generally limit shot weight to no more than an pounce & velocity no more than about 1200 fps. For this use Bullseye, Red Dot & Green Dot have served me very well for a number of years.
