Yesterday, on a particular forum that I participate in (usually by ridiculing the mall ninjas and Rambo wanna-be's who think that they're big and bad) a member sent me a message asking for help in customizing a Remington 870 shotgun for home defense. He was all set to put a side-folding stock and some kind of accessory rail on it and wanted my suggestions as to what he should put on. He admitted that he'd gleaned from my prior public posts that I had some experience with fighting shotguns.
Well he's right, and this is basically what I told him:
As far as an 870 goes, it's an excellent home-defense tool, but you'll come out ahead if you leave the silly stuff off of it. The next time you see a police car, if you can see it's shotgun, notice that it still has it's factory stock. 99%+ of military and law enforcement shotguns do and that's not because they're just not as hi-speed as the internet Rambos on these forums are. No serious combat shotgun has a side-folding stock or any other sort of collapsible stock and that's for several reasons. A proper stock gives you support, helps you to aim, provides balance, absorbs recoil, and is useful should you need to wrestle with or otherwise strike with the shotgun directly. By contrast, I'd be hard-pressed to think of a disadvantage to a solid wood or plastic stock.
Folding stocks, on the other hand, are awkward, unreliable, often make recoil unmanageable, and when the stress is high and you're moving fast, you aren't going to be messing with it anyway. It may look "cool" to some, but it tells the rest of us that the person holding it really doesn't know what he's doing. Posers have those on their guns. Professionals don't.
So leave that part of the gun alone and invest the money that you would have wasted on a folding stock on more ammo or other accessories like a Tac Star sidesaddle shell holder(a must, IMHO) or a good Surefire fore-end light. Again, there's no call for a rail when Surefire makes the best light on the market and it's part of the fore-end. Look up the Surefire 618 FA, or the 618 LF if you want an LED, and go with that. Yeah, it's pricey, but what's your life worth? If you want a defensive tool that will really come through when you need it, there's no substitute for this one.
Also, avoid stupid stuff that you see posers with in the magazines and on websites. This includes lasers, bayonets, heat shields, breechers on the muzzle and other crap intended to make the shotgun look "bad-ass". And leave the slings off of it, too. You're not carrying it on a 20 mile march and it'll just get caught on stuff when you're rushing.
In sum, Minimalism is the way to go, and a light and extra shells are all you really want. Keep the stock, add a Surefire front end, mount a sidesaddle extra shell carrier for $25.00 or so, and add a magazine tube extension such as made by Remington themselves or Choate Machine Tool. The extra shot or two that they give you are worth the money. If you still want four more rounds, put a speed-feed stock on it. These handy stocks look like factory stocks but have two spring-loaded shell tubes--one on each side--and each holds two more rounds. Using those on-gun holders, you can have up to sixteen rounds on the gun, giving you all that you'll need to end a fight without scrambling for extra shells in the dark.
Do these things and you'll have a fighting shotgun on par with most anything in use today by the average professional law enforcement agency that uses such tools.
And then get out and PRACTICE with it until your load, unload and malfunction drills are second-nature and you can hit your target dead center from 10 and 25 yards with shot and 25, 50 and 100 yards with 1oz slugs. (hint: reduced recoil are the way to go. You're not trying to drop a trophy buck at 150 yards...reduced recoil shells have all the power you need without the jarring recoil that slows follow-up shots and takes all the fun out of practice.)My own 870, waiting on it's Speedfeed stock to arrive.