I looked for months and never found a drilling that was still available and worked for me.
The one that I was ready to purchase that had sold was a Sempert Krieghof with a .22 barrel insert. After researching the various makers of vintage drillings I found they had a very good reputation.
Drillingman might have some recommendations as to other makers to look for, his knowledge is very deep in this area.
Also I have seen a few lower prices on newer drillings, Cabelas and Bass Proshops both have Drilling's in their gun rooms.
Are there any specific makers you are looking into?