American Select is also an excellent powder of which I use quite a bit. There are a lot of 7/8oz loads out there, and one rule of thumb I have been told and found true is a 7/8oz load needs to be pushed at least to 1,200fps to get a good pattern. I have just started using American Select at 1,300fps. The psi is around 7,000 and my patterns open up a little more with the added velocity. I use this in tightly choked damascus doubles and it is proving to be an great load. In regards to 3/4oz loads, there are a couple good recipes using Clays and the 12SO wad, but as has been mentioned, Promo and Red Dot are good powders. In the Oct/Nov issue of Clay Shooting (I think that was it) magazine there was a long article on 3/4oz loads. It seems the author got better results when the loads were pushed faster. Try 8 1/2 size shot for more pellets per load.
