I have a Remington 870 Police that I keep for home defense. I played around with extended magazines but have since gone back to the standard tube. It has a number of advantages. Granted you loose 1-2 shells but from my research, defensive shotgun fights that require more than 1-3 shells are incredibly rare. Tom Givens posted an article on something to this affect a while back IIRC.
The advantages of a stock (4 round) tube:
1) It's as reliable and simple as it gets. No multi-junction extensions to ensure are fitted together properly, no barrel clamps or braces to change point of impact with slugs, just a straight tube to cleanly feed shells into the action. Also simplifies field stripping and cleaning.
2) Increased durability over extensions. I have read of extended mag tubes, especially those without a brace, breaking off at the threads. One alarming report regarded a police officer who responded to a bank robbery. He grabbed his 870 out of his cruiser, smacked the extension in the process, and his magazine tube came apart spraying shells everywhere. Not good. Also almost the entire magazine tube is protected from dents that can impede feeding vs the much greater exposed surface area of an extension.
3) Maneuverability is enhanced. For me, the difference in a stock tube vs an extended tube is dramatic when transitioning from targets and when holding up the shotgun for extended periods of time. A person may need to hold the shotgun unsupported on a door or live subject for quite a while. The standard 4 round tube keeps the balance of the gun between the hands, reducing fatigue. Those extensions put weight at the worst possible point on the gun, the end of the barrel.
4) One handed operation and reloading. Tying in with maneuverability benefits, ditching the extension can make it easier to manipulate objects such as cell phones or medical supplies with the off hand while still holding the gun with the strong hand. It also better allows the gun to be trained downrange during reloading from a sidesaddle or magazine pouch.
In the end, it doesn't matter how big and strong you are, the standard 4 shot tube makes it easier to handle the gun and you might not be the only person in the household who might need to use it at any given time. Research and past experience tell us the capacity is statistically more than enough for the vast majority of defensive scenarios. A backup gun, often in the form of a pistol or revolver, is always a good idea no matter what you weapon's magazine capacity. Also learning to reload from a sidesaddle or other on-gun ammunition storage system is very important. Keeping the gun topped off is a great skill with the tube-fed shotgun, no matter how many shells it will accept.
So that's my reasoning for keeping my house gun extension free. Just thought I'd point out some reasons for doing this that I think are often overlooked. Try it sometime, you might really like it!
-Spunk Puppy
