I use a Fiocchi 2 3/4 plastic clear case for 12 gauge with 75gr of Swiss 1 1/2 black powder a thin overshot wad over the powder then a Win AA red wad then shot and then a six pointed crimp. I use a Mec 600 single stage press and you have to slowly in stages lift and lower the handle at the final crimp station in order not to crush the bottom of the case. I'm getting 1175 f.p.s.
Yes, there is more plastic fouling but the loads perform well at clays and live birds. I regularly run 25 straight at skeet with this load.
I've tried similar loads and not succeeded. Maybe I need to try again. The amount of plastic I got the last time was daunting. I don't know how the shot squeezed down the tube it was so bad.