The Mini-14 is reliable with large capacity mags, while the Mini-30 has problems.
First thing, for accuracy, is get rid of the loose fitting wood stock... or bed it as would be done with an M14/M1A. I replaced my Mini-14 stocks with Choate E2 style pistol grip stocks... which are legal on post-ban Mini-14's if you add no other AW features (such as flash suppressor or bayonet lug). The Choate is available in very well done camo.
This is NOT a 400 Meter target rifle, but it IS a very good 0-200 M carbine. With the factory stock, expect 4-6 groups at 100 M with 55 gr FMJ (M193). With the Choate stock or bedding, you can cut this in half, and expect 2" groups with scope.
I suggest you buy stainless, I have had NO problems with mine, and NO rust. The finish is a gray bead blasted matte finish, very non-reflective.
The best mags I have found are the 20 and 30 round PMI aka Precision Mag(also sold as Federal Ordinance) mags. I have had flawless functioning with these.
The Ranch Rifle version is very easy to mount a 1" tube scope. With the supplied rings (yes, Ruger gives you the rings) the largest objective you can fit is 40mm, plenty.
I clean my rifles after each outing, but if needed, this rifle could easily go 1000-1500 rounds, maybe more, without cleaning, and function just fine. It will run with no oil, though I don't recommend this.
This is the saddle rifle of the 21st century.
No, it is not as accurate as the average AR-15 or CAR, but it is not as expensive either.
It will digest just about any reasonable ammo you wish to fire in it.
I have has misfeeds with Ramline mags.
No, you cannot use or convert M16 mags. If anyone says you can, I challenge him to show me his converted mags.
If Ruger had been smart, they would have designed the rifle to use USGI M16 mags, and I am still surprised no one has come out with a kit to modify the mag well.