First-time poster with honest question. I'm buying a shotgun for home defense and hunting purposes should the need for survival arise soon (have numerous rifles already but no shotgun). But it's been a LONG time since I've been around a shotgun and I have several extremely basic questions. First, will the Mossberg 500 do me fine for the two purposes above or do I need to upgrade to the 535 because it can use up to 3 1/2 inch? Second, what's the difference and why do I need to care? Keep in mind I only need it either to unload...