When using a shotgun in a defensive scenario — whether from bad guys in a home defense situation or angry wildlife in an outdoor/hunting scenario — your best bet is to take advantage of every break in the action to reload. Gunsite Academy calls this "tactical reloading" and instructs students to reload immediately upon neutralizing a threat. In a recent Ladies Shotgun Course I took there, we were taught to keep sliding shells into the magazine at every opportunity. Shoot one, load one, to the extent that you're able.
But sometimes you're not able. We only do a tactical reload, as instructor Il Ling New told us, when we can and when we want to. "When you want to" is almost all the time. "When you can" is different — if you're still under immediate threat, you can't pause the action to slip five more shells into the gun.
Maybe the bad guy is still advancing. Maybe there's two more bad guys behind him. Maybe your first few shots failed to stop a charging grizzly bear and he's still charging. Whatever the reason, you've shot and shot and shot and you get to that "click" that tells you the gun is empty, and the threat is still immediate.
At this point, when you're sure the gun is empty, a speed reload of a single shell is your best option. Load one into the ejection port, shoot. Load another if you need it, shoot again. With practice, it can be done very quickly. Here, Gunsite instructor Mario Marchman teaches the fastest way to speed reload.
