Common usage - or misusage, actually - will probably always prevent such matters from ever being thoroughly settled. The ATF form 4473 that we've all grown to cherish, for instance, has a box for identifying the type of firearm, and lists the choices as "rifle", "shotgun", "revolver", or "pistol". And then there's Remington's backer card for their blister-packed magazines, with the word CLIP emblazoned across the top. Does Remington's usage effectively legitimize the term, then? I think most of us would say it doesn't. But what about the ongoing debate over the ".45 Colt" vs. ".45 Long Colt"? The predominent argument in support of the legitimacy of the "Long Colt" designation cites the use of that name on boxes of ammunition marketed around the turn of the 20th century, presumably to prevent confusing the ammo with the concurrent, shorter, .45 Schofield round.
Along this same vein, here is another potentially confusing issue that occurred to me a while back, concerning the regulations in some parts of the country permitting only shotguns for deer hunting, and not rifles. What, exactly, makes a long gun a "rifle"? I have always believed that the defining feature was a rifled barrel. But now that rifled shotgun barrels have claimed dominance in the deer camps, where is the line drawn? A legal definition based on cartidge/shell design would be almost impossible, considering the occasional manufacture of brass hulled shotgun shells over the years. So...?
Finally, to dump a little fuel on the clip/magazine issue, I'll point out that, technically, the term "magazine" is almost universally misused by those of us in the know. To be completely accurate, that thing we stuff full of cartridges and jam up into our firearms is rightfully called a "detachable box magazine." In general, "magazine" is used to describe a storage space, such as the powder magazine on a Naval vessel. As it relates to guns, the term "magazine" correctly describes any place on a firearm designed to store and feed ammunition, such as the integral magazine on rifles without detachable boxes, or the area in an M1 Garand into which we insert the en bloc clip.
Okay, enough. I'm.....
OutAtTheEdge