Smoke-

As the old whitebeards up on the ridge say: "...every last one of them..!!"

Let us know how you do with two in that .50
I think Daryl has a fine point on air compression and care taken in your load column.
Might want to do some experimentation to ensure you get a safe loading process.

Your velocity with 80gr on one ball sounds pretty zippy!

Cheers
Tinker