My friend was just at the house and he has mounted 48's on Krags and has this to offer.

Because the side is very rounded where the sight is to be mounted care should be taken to make sure the base it square and level.

He sets them up in the mill and uses a carbide 3/16" end mill to break the case and mill a flat spot. Then a normal drill and tap job as the metal under the case is soft.

MP Sadly Deceased as of 2/17/2014