Re: 12 ga 1oz slug help
I cast the 1 oz slugs from clip on wheel weights. Using Unique I'm at about 6" at 50 yds with my fully rifled Mossberg. I didn't bother trying for anything better. That's more than sufficient for my needs. My personal experience with Lee slugs is that changing the wad makes more of a difference than changing the powder. I use Unique because I use it in everything and have a lot of it on the shelf.
Oh, and I always put a card stock disc between the slug and the wad.
If at first you don't succeed, shoot, shoot again.