Some Slow Pistol Powders work well in the Shotgun. The only one that I know personally to never use in 12 ga is H110. It had a Flame out, then reignited and opened the Action on my Gun. Lil Gun is in the same Powder Series as Primex 513, which is excellent. Most of the Big Ammo Companies are using some of the Primex in their Slug, Buck and Steel Loads. As far as Reloaders can get, Lil Gun works well with IMR 4759 being discontinued.
Greg
AKA 12 Bore