I don't really get that shotgun thing? It might be useful to blow zombies away from ten feet, but anything else? I guess I'd rather have a pistol or rifle, so I could do some target shooting. Which seems much more fun to me, since you actually need some training and skill?
But since gun laws here are very strict and there aren't many shooting ranges (and those existing are filled with rightist morons) I guess I'll keep it to a crossbow or something
Shotguns are useful from 0 feet to 200 yards, depending on load. For home defense, they have no equal because they are absolutely devastating with either buckshot or slugs at the typical home defense ranges. Despite what you see in movies, you do actually have to aim a shotgun, you can't just wave it in the general direction and fire it - at least not if you wish to hit the target. And if you wish to hit a moving target (shooting skeet, clays, hunting birds, hunting deer, hunting *bear*), you must also have skill and training.
To give you an example of how it works: With a 12 gauge shotgun, assuming it hasn't been fitted with certain muzzle devices to change the way the thing throws projectiles, the "cloud" of projectiles it throws expands approximately 3cm per meter of linear travel. That means that if you fire on a target from ten meters away, you have a 30cm area in which all your projectiles will land. If you are using the famed 00 Buckshot type rounds, that means that between 8 and 11 9mm lead projectiles will hit the target at around 1300 feet per second (or 396 meters per second). That's actually faster than some 9mm rounds. In terms of the damage it will do, that's like dumping between 8 and 11 9mm rounds into the target - except they're hitting all at one time and they greatly increase the chance of you getting at least one hit. If you're firing rifled slugs, you have about one quarter or less of that probability of error, and you're throwing a huge chunk of metal downrange - devastating out to 200 yards/150 meters.
Militarily, Europeans tend to favor submachineguns for the same sorts of things we use shotguns for - such as house clearing, close quarters combat, trench clearing, etc. The repeater shotgun is just not something that Europeans seem to get - seeing as how most European shotguns are *very* expensive two-shot weapons used only for sport or hunting.
The shotgun is probably the most versatile weapon one can own. Simply by changing the load, you can hunt everything from varmint (things like annoying squirrels and pigeons) to big game (elephant, grizzly); you can launch flares with it to signal others, you can use it in a less-lethal configuration (rubber bullets, or even beanbags!) if you just want someone to leave you alone, if you're in the military you can use the minigrenade rounds, you can fire tear gas from it, you can use it with noisemaker rounds to scare off flocks of birds, you can use it in combination with a special grapple to throw a line to someone for rescue, the list goes on and on. Here in America, we use the shotgun for all of the above and more.
.