There are some places in the world where gun control can be more effective and some where it will be less effective.
After Dunblane, Britain went for an outright ban on handguns (apart from a handful of loose powder muzzle loaders and carbine conversions) and a ban on all semi autos larger than .22 calibre. Britain also has draconian rules on who may own a gun, under what circumstances and also regulates the sale of ammunition so that gun owners may only buy as much as the police consider they have a legitimate use for.
These bans were fairly effective in removing privately owned guns because there was public buy in to the idea, good cooperation from gun owners (who as a group were some of the most law abiding people in the country), because there were relatively few guns of the type being banned in the first place, (less than a third of legally owned firearms in Britain), because there were even fewer in criminal hands and because Britain is a small island nation with pretty good border security.
None of this stopped a taxi driver from murdering 12 people with a bolt action .22 rifle and a double barreled shotgun in 2010. These types of weapon are generally intended for pest control and there has never been any serious call to ban them. They are a necessary farming tool.
The USA is a huge country saturated with guns. It has a porous land border with a third world state that has a huge problem with violent militarised criminal cartels. (Yes, you Canada!) It was founded by revolution against monarchial government. It romanticises it's pioneer tradition when settlers expanded civilisation into the wilderness armed against large predators. It reveres the cowboy myth and the concept of individual liberty. The right to own guns is entrenched in law and a large proportion of the population strongly supports this.
Guns are in criminal hands in the USA to an extent almost unimaginable to people in other Western countries. Muggings and robberies using guns are routine. As has been pointed out, the death toll among young men in the urban drug trade is astounding. Many law abiding people in high crime areas feel the need to own firearms for self defence.
As a purely practical matter, how could you institute a British style ban on handguns and semi autos in the USA? Imagine you somehow manage to pass the necessary laws. How could they be enforced? How could you prevent people having access to illegal guns?
I simply don't think it's possible, in the same way that generations of prohibition have not reduced the availablity of illegal narcotics. In any event it would not stop gun massacres being carried out with the remaining legally owned bolt action, pump action, lever action and single shot guns.
Having said that, lone nut gun rampages tend to carried out with legally owned weapons and I believe it's worth an effort to try to restrict crazy people's access to them. There is a lot of middle ground between gun bans and unrestricted access. For example, it makes a heck of a lot of sense to me to ensure that a firearm owner can use it safely. A firearms license that required a safety course, background check and police interviews with family, friends and coworkers would help reduce impulse gun crime.
Nothing however will completely prevent gun massacres in any country. Germany has banned paintball and laser tag on the grounds that they "train people to kill" ( while studiously ignoring much more realistic and violent -and lucrative - video games). Sooner or later there will be another gun massacre in Germany. And in Britain. And in Norway. The best we can do is make it harder for unstable people to access weapons, but at some point you just can't tighten gun laws any further.
The question is what level of gun control is both politically feasible and practically effective for each individual country in order reduce the number of crazy people having access to guns. The USA has fewer options in this regard than Britain.
I don't consider shooting stray dogs legitimate unless its attacking, or clearly about to attack someone. And I'm a pro-gun 'merican.
