bls,
The 9.3X74R is very capable of making a clean kill on the largest game in North America. The 9.3X72R, not so much as others have said. As to your tightly choked 16ga barrels, any word suggesting NOT to shoot Brenneke slugs in them is BS.
As our fellow member "Kuduae" (Axel) has taught us, any Austrian or German maker worth his salt would have regulated the left shot barrel of your drilling, loaded with a Brenneke slug, to shoot very close to the same point of aim as the rifled barrel at 50 meters for a front trigger then rear trigger "1-2", pretty much making your drilling a double rifle. If the right barrel does the same such would be pure coincidence.
I'm not sure how to get into the DoubleGun BBS archives but here is a link to another site noting the use of a Brenneke 16ga slug on a Russian boar here in the Upper Mid-West:
http://forums.nitroexpress.com/showflat.php?Cat=0&Number=243537&an=0&page=2#Post243537Do post pictures of your Ferlach piece as I'm sure many here are anxious to see your new find.
Mark