If I were going to attempt sealing primers and case mouths like this, I'd use something designed for the purpose. Not wax or hot glue or fingernail polish.

http://www.midwayusa.com/product/954332/markron-custom-bullet-and-primer-sealer-1-2-oz-liquid

I am not entirely sure if the front end of a blank even can be sealed. I have seen few blanks in my life, but I seem to remember that the case mouth is (or can be) folded back and crimped/squashed over itself (like the front end of a standard shotgun shell). I don't know how well you could seat that, with all the bends and folds in the metal. The crimped front of the case mouth might be a place where a wax glob could be used.

As someone else already mentioned, we're talking about revolvers here. Blanks don't get along with semi-autos, especially blanks covered with wax or other goop.