that's a lovegun.
A serious moment: I also learned the term "long gun" as a consequence of getting into ballistics. Nowadays these are pretty much divided into rifled and smoothbore guns. The smoothbores are by and large limited by law as shotguns, with exceptions made for blackpowder arms like the early US "Brown Bess" smoothbore musket.
An AK or comparable assault gun would be termed a long gun. Not sure how to classify a submachine gun like an Uzi.
~edit~ looked it up. The Brown Bess is a British design of the 1720s.