I do like that option. Can you fire regular cheap .22 rounds through a .223 rifle like that? Or are you risking damage of some sort? What is hi-cap? (sorry, combo of laziness and asking on behalf of lurkers)
No. Practically the only thing that .22LR ammo and .223 ammo have in common is a bullet diameter of approximately .22 inches. Virtually everything else about these two cartridges is as different as night and day.
This is typical of cartridge designations. The names imply much more than the name suggests and there are few circumstances which permit one firearm to fire more than one type of cartridge. Firing the wrong cartrige in a firearm is a recipe for disaster. All modern firearms have the cartridge type engraved on the barrel or some other visible part of the gun.
Only if you buy a special adapter, which will cost almost as much as a semiautomatic .22 rifle. But there are advantages to practicing with the same rifle you'll be using if/when the SHTF.
Back in the '70s and '80s, and maybe still today in some cases, even the military used such adapters in M-16s for practice and qualification for non line types, like moi.
I apologize for not getting back to you on that question about the Ruger .223 Min-14 Ranch Rifle.
You can't shoot 22 LR through a .223. You have a real need for cheap ammo. I just checked Ammoman, J&G Sales and Cheaper than Dirt for some current prices on the cheapest of each caliber. Unfortunately the only stuff cheaper than the mega-mass produced .223 (AR-15 or Mini-14)at about 30 cents per round (case prices) and 7.62x39(AK-47 or SKS)at about 20 cents per round ammo (case prices) is either .22 mag (also known as .22 WMR) at 20 cents per round or .22 LR at 4 cents per round.
.22 LR can indeed drop human size animals -- if with a brain shot or heart shot (used by Israeli assassins or deer poachers). But self defense situations make an accurate center head shot or heart shot hard to rely on.
Deer poachers and other hunters sometimes us .22 mag (22 WMR) since it has about 1.75 times the velocity and 3 times the energy of a .22 LR of the same bullet weight. BUT .22 mag ammo costs as much as 125 grain AK-47 ammo which has an impact equivalent to a 30-30. The 55 to 68 grain .223 ammo generally costs half again as much as AK-47 ammo -- given that both are equally available (we've had recent shortages where cheap versions of both were not available in case lots).
Outside of the .22 LR, .22 WMR, .223 and 7.62x39 the next cheapest are the other military calibers such as .308 which costs from 30 cents if you can find it to 50 cents per round.
Handgun ammo, OTH, such as 9mm can cost as little as 20 cents per round. Note that a 9mm from a handgun and a .22 magnum from a rifle have about the same energy and, perhaps, stopping power. Note that only the biggest magnum handguns can deliver the stopping power of the .223 -- and both such handguns and the .223 are regarded as barely adequate for hunting larger (northern) deer.
For your SHTF scenario, you want effective stopping power, semi-auto, large capacity magazines (20 or more rounds each), and cheap ammo. That boils down to 9mm handgun, or .223 Mini-14, or an AK-47 (the latter you might not be able to legally get in California). The .223 has a wide variety of ammo available -- from cheap plinking stuff to ammo specifically designed for maximum stopping power but minimum penetration through walls, and some for maximum penetration through windshields). Personally I'd recommend the Ruger Mini-14 if you can't afford an AR-15. You might find an AK-47 for half the price of a Mini-14. In either case, a 9mm handgun would be a good companion for all around carry -- and the situation of using the handgun to fight your way to your long gun.
I should say that a 12 gauge shotgun is great for self-defense -- but the ammo is expensive, you don't get 30-round magazines, and it isn't for plinking.