Testing went very well, thanks! The design was easy to put together, fit perfectly onto the zincs, and had no pumpkins. Loaded and fired the same as the factory 781s.
All the components I used to test these were from AMTEC, including the casings, blanks, and zincs. The only part not was the chalk, and that was a mix of mil spec orange dye powder and chalk from Lowes. The powder was tamped slightly into the nosecones to fill them.
For loading, I recommend placing a thin ring of RTV around the inside lip of the casing first, and seating your zinc. Allow that to set for a day or two. Then add your blank. If you are storing the round for any length of time, I recommend applying a very thin bit of RTV around the blank itself. Next, fill your nosecone with chalk, then tamp it, then fill it again to 1/4" below the rim. Apply a bead of super glue gel around the zinc, 95% of the way, seat your nosecone then twist it 1/4 turn. This will allow the air to escape the cone, then seal it 100% when you twist. Allow that to set nose down for a day or so for the glue to dry. After that, you are ready to fire.
GROG