UrbanMan's comments: I too have a Ruger 10-22. I also have two other .22 LR rifles and one handgun, another Ruger product - the Mark II. There are many after market accessories made for the Ruger 10-22,...from extra capacity magazines, to stocks both full length and folding, to scopes, bases and mounts, trigger kits, muzzle breaks (as if you needed one), and many others. The Ruger 10-22 cas it comes out of the box is as good as factory original gets. I would suggest adding some extra capacity magazines and none are better for the Ruger 10-22 than those that comes from the factory.
This means the Ruger BX-25 magazine (shown at right) which is a 25 round curved box magazine if you couldn't figure out the round count from the name. Pro-Mag makes a 50 round drum magazine which is worth looking at. I have tried many of the plastic magazines even the ones with steel feed lips but I would hesitate to recommend them.
Pro-Mag, 50 round drum magazine, shown at left, is another option. I don't have one and I think I'll be sticking with my factory 10 round magazines and the 25 round box magazine.
Double K makes essentially a speed loader pouch, advertised on Cabela's that shows two Ruger factory 10-22 magazines fitting into where you would normally carry the speed loaders for revolvers. I didn't even think about this, nor do I have any other pouches to keep my 10-22 factory rotary magazines, so I tried them in an old speed loader pouch - it's a tight fit but they'll work.
While many will take exception to my calling either a .22 LR rifle or specifically a Ruger 10-22 a necessary component of the Survivalist's firearms battery, I'll stick to my guns (no pun intended) and say that one is absolutely necessary.
From training to hunting small game there are many uses. Ammunition is cheap and a lot of it is easily stored in small spaces. While I also have an AR-7. It is a true survivalist's rifle as it stays inside it's butt stock and inside one of my Bug Out bags.