A few more thoughts about shells. All my shotguns are European and I simply do not buy "off-the-shelf" American ammo. I buy ahead each season and generally stock up on BPs and in the past few years have switched almost entirely to 2 1/2-inch shells. They work just fine.

Just returned from a grouse hunt where I used both 16ga and 12 ga guns, all with 2 1/2-inch shells.

Good, light upland guns don't need ack-ack. I think throwing up a barrage is a mindset and it doesn't go well with fine light guns. Just my thought.

If you really want, for some reason, 2 3/4-inch chambers make certain that they haven't been lengthened and that the gun is still in proof.