If you have a good pump or semi-automatic shotgun that you’re willing to cannibalize for this project, it’s the cheapest route. Remington 870s and Mossberg 500s are best for three reasons: They’re wonderfully reliable shotguns; they’re cheap in price but not in construction; and, there are copious aftermarket add-ons readily available for them.
If you’re willing to turn your 870 Express duck gun with a 28-inch barrel into a home defense dynamo, it’ll need a shorter barrel so you can fight with it without it getting knocked out of your hands by every ceiling fan or banister in the house. Sure, you can legally hack off its barrel provided it’s longer than 18 inches, but the biggest plus of buying an aftermarket barrel is that you can reuse the original barrel if you wish. MidwayUSA offers an 18-inch 870 barrel with a brass bead for $139. Mossberg 500 barrels are $99. It’s the way to go.
If you don’t have a decent shotgun to spare, worry not. A new, synthetic-stocked, 6-plus-1 round Remington 870 Tactical with an 18.5 inch barrel costs $319 from Academy. My budget shotgun of choice is Mossberg’s 12-gauge 500 Persuader for $371 at Cheaper Than Dirt. Alternatively, you can buy a used shotgun. Make sure it’s in good shape, as this is the gun you could bet your life on. You’ll probably spend around $225, and it likely won’t be with an 18.5 inch barrel, but you never know what your local pawn shop might turn up.
If you are converting a hunting gun, you’ll need a 3-round magazine extension tube for $50. Make sure it includes a sling swivel.
The full-length stock on your 870 or 500 is desirable. (FYI: there is nothing wrong with wood stocks, unless your bedroom happens to be in the Panama jungle during the rainy season, so don’t rule out a bargain-priced shotgun just because it wears walnut.)
While the cat’s meow is a tritium Big Dot shotgun bead from XS—it costs $71. But a dab of Cool Glow glow-in-the-dark nail polish from Wal-Mart on your standard brass bead for $2 will do. Even without charging under a light, it’s easier to see than brass when it’s Silence of the Lambs-type dark in your basement.
A shotgun is big and heavy, and even dialing a number on a cell phone, while also holding a flashlight or whatever is near-impossible while clutching the shotgun with the other. A simple nylon sling from Uncle Mike’s will cost you about $22.
Unless you’re an octopus, you’ll need a flashlight on your shotgun if you desire to shoot it and see your target. While Surefire’s DFS Series integral forend shotgun flashlight is the Cadillac, it costs $399. But a flashlight that costs more than the shotgun seems silly. So, I recommend something like the Tufforce New Gen.1-inch Tube Ring Mount that allows you to attach many types of flashlights to the side or underside of your shotgun’s barrel or mag tube. It’s about $18 from Amazon. Then you’ll need a flashlight with a pressure switch, because you’ll need to be able to work the light while death-gripping the shotgun’s forend. I’ve seen weapon-mounted lights as cheap as $19 at Wal-Mart and Amazon, but a flashlight is very important, so I’m not going too cheap here. Streamlight's ProTac 1 is $109 from Cabelas. That’s my choice.
Finally, I like extra ammo on my shotgun so I don’t have to fumble for it when Freddy Krueger comes knocking. And while I’ve tried Velcro tabs that stick on the side of my shotgun via adhesive, they eventually fall off. So either go with a plastic sidesaddle like that from Tacstar for $31 at Midway USA, or try a cheaper one like the Aim Sports at Cheaper than dirt for $10.
There you have it.
While some people prefer more junk on their shotguns than I do, including pistol grips, oversized bolt handles, red-dot optics or ghost-ring sights, I don’t believe these things are necessary in your home. The total price of my ultimate defender shotgun ranges from $331 to $538 depending on what route you go on the gun itself. Any way you look at it, it’s a lot of home defense firepower for the money. Place it in your bedroom where you can get to it swiftly and then rest easy knowing your family is safe.