Pete: I have had ZERO issues with Green Dot. I load 1 3/8 oz lead shot,but Not at low preasure, or velocitys. This load is impervious to cold Temp., and patterns well . I do not know what the preasures are. I use a Pacific wad and no filler and 6 point crimp. Fed Primer. See what other people (loading books) recomend for powder weights . their is data out their.
good luck
David Lien