Quote Originally Posted by Claven2 View Post
Did you use a filled for the hollow space left in the case, or are the powders you're advocating reasonably resistant to positional sensitivity to not matter much?
This could become a very long discussion (and maybe it should).

I worked up four loads that I have employed in 24 ga Fiocchi shotgun hulls (some with a shot wad acting as a sabot), and in the brass Magtech 24 ga shell. All loads were under a 480 gr custom cast bullet, and are quite mild, my objective being 1100-1200 fps. None used filler, except the shot wad which took up all empty space, and only the Unique load was seemingly unaffected by position. I found H4227 the slowest powder that would burn consistently at the low pressures I employed (~12,000 psi) - slower powders tended to just spit out the bullet along with mostly unburned powder.

Unique - 18.0 grs - 1150 fps
SR4759 - 35.0 grs - 1100 fps
AA5744 - 35.0 grs - 1100 fps
H4227 - 35.0 grs - 1100 fps

I intend to try some IMR Trail Boss (15.0 grs) this winter. Trail Boss is VERY "fluffy" - 15.0 grs would consume as much space as 30 grs of Unique and 40-45 grs of the others and might be the perfect powder. I'll report back.