For a combo gun (two bbls) I like The Valmet 412's,. They could he had in shotgun, combo gun or double rifle.
Best part is, you could buy an action and then buy any one of the more than 25 different bbls later!
Valmet also offered a QD scope mount,
And it's an all steel mount that goes on and off easily, and accurately! Here's a target from one of my 12ga - 30-06 bbl. sets, taking the scope off and putting it back on after each shot,
I shot a lot of big game with that combo, including 3 big bull caribou in one day. Here's one of them,
There are still plenty of 412's forsale, like this DR still new in the box,
you just have to look around a bit.
Great guns, very accurate, with many options!!
DM