Please don't buy a Mini 30, they are garbage. High capacity magazines have always been a source of frustration in the Mini 30 world. Your only source of hicaps is aftermarket, usually junk, and even the "good ones" don't always work. For the sake of consistancy stick with 10 rounders.
You may encounter some 20's that work well, but you will probably have 1 good mag for 5 that suck. Mini 30's also have inferior accuracy and they are too much money for what the offer.
On paper, the Mini 30 seems to have a lot to offer, but in reality they are poor performers.
A cheap WASR from Century is a much better rifle than a Mini 30. Availibility of magazines is obviously much better and it offers much better accuracy compared to the Mini 30. A SKS with an integral 20 round magazine is also another consideration. If you do buy a Mini 30, I would bet you sell it in less than a year when you realize the only good magazines are the 5 rounders that came with it*only 5 rounds in a semi auto really sucks, unless its extremely accurate...which these arent* and that the best group you will achieve will be something like 5 inches....no kidding. You may do 4 with good ammo, if there is such a thing in this caliber. My advice would be to get a Vector AK underfolder with a few 30 round magazines and some Wolf ammo. You will have a much better weapon than a Mini 30. Check out www.perfectunion.com, this is the Ruger Mini equivalent to this site.