With a shotgun you’re firing a number of individual rounds (pellets) depending on the size of the buckshot used. Depending on the pattern and spread you’re liable for all of those. In any home defense situation it’s critical to recognize what’s behind the target and also consider overpenetration. Check out the “Box ‘o truth” videos on YouTube, they do a really good job of simulating walls and overpenetration. Pumps can be problematic in these situations too, sometimes people “short shuck” the pump and jam up the gun. Whatever you wind up using, train with it. That’s super important. As far as the springs go, it’s my understanding that the wear on springs comes from the use of them, flexing and unflexing, and it’s better to leave the spring compressed rather than frequently working it. I’m pretty positive you’re fine leaving it loaded. Mine has been loaded for quite a while and still runs perfectly. I personally use my carry handgun because I’ve got 50,000+ rounds training and competing with it. Use what you’re comfortable with though, just learn about using it safely in a “social” situation.