Few firearms beat the shotgun when it comes to guarding your home. An age-old favorite due to its high versatility and devastating power, it is most capable in close-quarters combat and engaging a combatant head-on. These firearms generally come ready-to-use, and with a few nifty weapon accessories can become more than just added weight.
The best sling option you can get for a shotgun is one of the two-point variety. Three point slings can complicate use, and a single-point one would be ill suited to running and moving through brush. Since shotguns mainly get used on long patrols or quick security checks, a side-mounted two-point sling would work well in most cases.
Sidesaddle or Stock Carrier
Every shotgun has limited magazine capacity because of how the firearm parts are arranged, so you will want a way to carry an extra reload on the gun itself. A buttstock carrier or a sidesaddle gives you that option. That said, using the latter with a Mossberg that has an aluminum receiver could deform the pins from long-running recoil action. Even Remington guns pose that problem, but not to the same degree.
A tactical bright light attached to your shotgun is good for deterring use of lethal force. The best variety comes integrated into the pump, with newer models carrying unbreakable LED bulbs capable of withstanding recoil, and running hours on a single set of batteries. You can also get a replacement fore end with a rail that can be used to attach the light. Just pick a light and mount of good quality and durability.
Extra Shell Carrier
Efficiency is vital when using a shotgun, and a shot shell holder mounted to a belt clip can change the game significantly. A modular pouch can do much the same, but scores low in versatility. You could use a shotshell card alongside a rifle rig. This is a slim card with hook Velcro on one side, which you can zip-tie to something in order to expedite ammo setup. Putting loop Velcro on the shotgun gives you something to use as a sidesaddle.
If you ever need to pick two out of the above four, you should take the buttstock and the weapon light, because those two take care of the prime essentials when it comes enhancing to a shotgun’s functionality: an option for faster reload, and a way to see and identify targets more quickly and clearly.