I do have a combi gun. It is a lovely little thing circa 1937, Kersten lock, deep engraving and tasteful gold inlay, 16 Gauge 2 1/2" over 7x57R.

My application of said combi is sometimes using it for deer hunting as a single shot, (and occasional moose) with some bird shot loaded for the occasional grouse I happen to see along the way back from my stand. I too do not put any stock in buck shot. I have seen triple ought work effectively at 20 yards, but it made a mess of the deer with lots of ruined bloodshot meat and didn't penetrate deeply..... Deep enough to kill but certainly no pass throughs.

The other application I sometimes use it for is as a bird gun as first consideration with a few cartridges in my pocket should I happen to stumble across a black bear.

The shotgun shells are all but impossible to buy anymore, so I buy 2 3/4" factory shells and modify the length with a crimp cutter and roll crimper for my drill press. Cutting off the crimp around the circumference of the shell then dumping out a tiny measured amount of the shot, just enough to place a thin waxed cardboard circle on top of the shot gives me just enough plastic to apply a roll crimp. And, voila! I now have 2 1/2" 16 gauge shells!

Would I buy another combi gun? I'm not sure I would.... I have drooled over the Heym O/U currently available, but I have mixed feelings over it. I prefer to bird hunt with a SxS 28 gauge, and I find I do like a second shot quickly available for the type of rifle hunting I do. I find that the combi gun's greatest appeal is that it is super light weight and fits very well. I tend to bring it along with me when my goal is more about fresh air and appreciating the outdoors than when I am involved in a serious hunt.

I have yet to try rifled slugs in the 16 gauge combi gun and will at some point work out the concern about rifled slug shell length in my old school short chamber. Maybe if it works out, I will find I have a useful two shot deer gun with a slug and a 7x57R bullet........ I'm still pondering this notion.