Rob, Ordinarily I'd be downtown by now, shooting pictures, but it's hotter than blue blazes out there, so I'll stick around and philosophize.
An easy supply of guns isn't the problem. The problem is people who use guns to perpetrate crimes.
Humans have armed themselves since long before the beginning of recorded history, and they're not about to stop now. The arrival of guns -- even ancient wheellocks and flintlocks, made a huge difference in human interactions. The gun revolution was even more striking than the introduction of the English longbow, which revolutionized warfare. Then we progressed through a series of minor revolutions such as breech-loading, rifling, etc., etc., and finally developed the Gatling gun, the water-cooled machine gun, the tommy gun -- so Chicago criminals wouldn't be left out of the march of progress, and Wegee would be able to get his gory pictures -- and eventually learned how to produce the ultimate weapon by disrupting atoms.
There's no way to limit the number of guns. If you make gun manufacture and possession illegal in one country, guns will be manufactured in another country and smuggled in by criminals for criminals. If you make gun manufacture and possession illegal in every country in the world only criminals will manufacture guns, but you can be sure they'll manufacture them just as they manufactured booze during U.S. prohibition.
When a jurisdiction tries to limit the ability of honest people to arm themselves, what they're actually doing is trying to make sure only criminals have guns, though in sane jurisdictions they insist that their enforcers -- the cops -- are armed. But what's the difference between an armed cop on the corner and an honest man who's firearm trained, alert, and carrying a weapon? The only difference I can see is that the cop is "sworn." When I was mayor, during big downtown events we'd sometimes use a group of volunteers called the Colorado Mounted Rangers to help keep the peace. My police chief would grumble about "hobby cops," but the Rangers were well-trained and responsible. One of them was a deacon in my church.
You're right. Only people in combat need assault weapons. But people who don't know anything at all about guns will call any rifle -- semi-automatic or even single-shot -- with a flash suppressor or a pistol grip an "assault" weapon because it looks hairier than the semi-automatic rifle next to it that's mechanically identical. I don't know about other countries, but in the U.S., full automatic weapons of any kind, and rocket launchers, are outlawed.
Guns don't kill people. People kill people -- either deliberately or by "accident" through ignorance. And people kill people with guns, knives, garrottes, baseball bats, crowbars, shovels, automobiles, etc., etc. If you lock up or execute all the people who want to kill, you'll solve the problem, but you won't solve it by futilely trying the rid the world of guns.