German/Austrian combination guns are my thing! I am quite happy to say that the advent of the S&B ammo on the US market is the best thing to happen to us drilling and cape gun lovers. The 9,3x72r ammo performs well and is quite similar to the original loadings. The 8x57IR in S&B regulates right on in all four guns I have with that as the rifle barrel. The 7x57r with the 175 gr cutted edge bullet regulated well in the one drilling I tried it in.

The 9,3x74r was a different story. I have had erratic results with the S&B in the 74...I suggest you stick with RWS or Norma in the 9,3x74r.

Don't ever sleeve the 16 barrels, unless they are a mess. Buy 65mm shells like Gamebore and shoot away. While a bit expensive, how much do you shoot the 9,3x72r, anyway? Cape guns and drillings won't take the kind of shooting volume that bolt rifles do, and they were not meant to take out to the back 40 and blast off 1,000 rounds. I shoot no more than a couple of rounds of rifle ammo through any of mine in a season. They were not meant for allot of shotgunning, either, at least the drillings weren't. Drillings tend to loosen up quickly.
A little was trimmed here and there to keep them from being too big and heavy.

I've killed 5 deer and a black bear with the 9,3x72r. It is very effective within 100 yards...maybe 125 and performs about like a 35 Remington. The biggest problem with the x72 is the crummy bullet design we are stuck with, and we CANNOT load it any hotter!!!!!! Don't even go there!!!!! I wish I could find a little tougher bullet for the 9,3x72r for black bear hunting. The traditional 193 gr flat nose is too soft.

Enjoy hunting with something a bit different. Those old calibers and bores worked then, and they still do...Classics...