Yes - very interesting project.
The previous system of enlarging an undersized projectile was called the Delvinge system. In that, the breech plug was hollowed out to hold the charge, then the shoulders of the plug were used to slug up the "ball" to fill the rifling, again, with 3 blows of the rod ie:"throwing the rod upon the charge".
At the start of the civil war, the War department bought military rifled muskets from Austria (& maybe France?) some of which had either the Tige or Delvinge systems.
Since both rifles needed 3 throws of the rod, it was felt that the standard system then used by the US military would suffice as they, at that time had the same loading practice, when loading muskets.
I suspect there would have been problems with projectile type as well as size & the charge size (paper ctgs) as well.
A logistical nightmare.