I've got a Sauer 3000. The Gun barrels will not shoot the same POI as the rifle barrels for one very simple reason. When it is selected on Gun, the rifle sights lay flat and cannot be used.

When on rifle, the right trigger will fire the rifle barrel. The left trigger, the left gun barrel. Where that goes is anyones guess. And I spose you would have to take it to the range to check. My only experience doing that was when I let a 30/06 round go at a mob of ducks, followed by a bunch of 4's from the left barrel, under the impression I was shooting the gun with both barrels. Dumb, but hey, I managed to miss the ducks, with the 30/06, same as I missed with the shotgun barrels!

My understanding is you can shoot slugs through any shotgun barrel, taking into consideration chamber size etc. I certainly would put any slug through my drilling in a heatbeat unless someone who knows here tells me different. But at least in my Sauer where the right barrel shoots in relation to the rifle sights is irrelevant, as I cant make it fire no matter how hard I pull the trigger. Where the left barrel shoots may be relevant, but in my experience of shooting pigs with slugs or shotguns using buckshot (and I do have photos)sights are not that important as such. With my Sauer I hit them with the Gun at the up close, and hit them with the 30/06 further out.

I've always considered Drillings a gun to take when you are shooting bunnies or ducks or something, with the chance at a pig or deer. In itself, it is a single shot rifle, and not a particularly good one when compared to something in a Martini action etc. Its not fast and with the sights provided its not accurate. But it is good on a goose swamp when a hog pokes his head up at 150 meters and your mates all have 12x12's.