Does anyone have a loading for 12ga Rio Hulls, Fio primers, and Clays about 1200 fps and 1oz of lead?
When I was loading Clays, I was loading 20.0 grains of Clays for 1-ounce with either a Rio primer, or the Fiocchi Fio 616 primer and either a CB6100, or the Gualandi GU-1225.
More often than not, the Fiocchi Fio 616 don't perform well with Clays powder when compared to the Rio G-600. But there are certain sweet-spot loads (albeit rare) where they do perform Ok, and on rare occasions, better than the Rio G-600. But that's more the exception than the norm :
Someplace I have matching chrono data for ~20.0 grains of Clays in that load, but with the CB6100. The Avg velocity for the CB6100 is about 30-35 fps slower that the GU-1225.
One thing to watch for if you load the CB6100, is to make sure that you have "enough" powder to keep the edge of the powder cup of the CB6100 above
the top edge of the basewad in the Rio blue hulls.
18.5 grains of Clays in a Rio blue for 1-ounce will "work" (with any primer), but it's my opinion that this is too light of a powder charge. Pressure will be too low, and you may risk having the lip of the power cup on the CB6100 catching on the top edge of the basewad and canting the powder cup.
You can cut inspection slots at the bottom of the loaded shells to see if this is happening:
With 20 gr of Clays, there should be a visible gap between the cup and basewad:
So I'd say start with 20.0 gr of Clays until you find an actual reason
to load less.