Many years ago I discussed the idea with a very experienced LEO/reloader.
He told me to be careful - he thought that reversing the commercial HB wadcutter greatly reduces the volume of the case compared to the powder charge. This would result in higher initial pressure but not necessarily an increase in velocity. Higher initial pressure could "blow out" the thin center of the soft bullet and cause it to stick in the barrel.

Another concern of his was that the reverse "shuttlecock" would cause the bullet to "swap ends" at anything beyond "handshake range."

I made a few with a slightly reduced charge of Bullseye and shot them into gallon jugs of water. They flattened out to about quarter size, but did not exit the plastic jugs (less than 6" penetration).

We considered getting a HB wadcutter mold and using hard alloy and a gas check on the base, but never did.

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6/23/2022