800X is a tricky powder. It meters much better in single stage loaders than it does in progressive loaders with the exception of Spolar. It is a large flake that does not flow as well as smaller flake powders. I also find humidity changes seem to make a big difference so check your powder drops when you get started.
On a 600jr it will work flawlessly because the handle goes up and down multiple times more than the bar goes back and forth. So over multiple stations use, the powder gets repeatedly vibrated down, the same way over and over again so the powder drops are very equal. on a 650 , grabber or later loader powder gets dropped every time the handle gets lowered and then raised. And if you dont do it with the exact same speed and exact same clunk at the bottom and top of the cycle the powder can be slightly different in drops.
When you go on the powder makers web site look at Federal hulls. Some decent loads there. Do figure out what pressure level you are after. A 20 will run a bit higher than a 12 so you wont find many 5-6,000 psi but you can find some 7-8,000 psi. Figure what your gun was proofed at and look for a 60-80% service load. I try to keep my loads at 8,000 or less. A lot of options at that level on both Alliant and Hodgdon.
