My dad has the double barrel coachgun version with 20" barrels in .410. It's a nicely made, beautiful, light, handy grouse and rabbit/hare gun. It's a great gun for when it starts getting real cold and the recoil of a 12 ga becomes punishing with cold hands.
He can't use slugs though, as both barrels are not aligned (too short for proper alignement) and the shots cross each other rendering it hopelessly innaccurate.
However, it does fine with a load of no. 6's or 7 1/2's in 2 1/2" shells.