clarification: The Mini 30 shoots the 7.62x39, The Mini 14 shoots the 5.56 same as the AR15
(danger will robinson!) okay which is better?
There's a .300 Blackout chambered Mini now as well, and it's quite easy to have one reworked to the 7,62x40 Wilson Tactical round, which I 'm of the opinion beats the .300BO to all get out [based on around 7500 rounds of .300BO downrange in two rifles.] There were also some Mini-14s sold in the .222 Remington [NOT .223!] chambering, for distribution in some countries where military cartridges like the .223/5,56mm NATO are prohibitado. They're pretty much collector's items, and are generally priced accordingly when one does turn up, but there are a few out there.
All that may change: Ruger has introduced an AR-15-type Ruger rifle with a quick-change barrel, offering the option of changing to some alternate calibers in about three seconds with the flip of a lever, a twist of the barrel, and a reinsertation of the alternate.
It might just be that Ruger will apply a similar mechanish to the Mini-14, making it even more versatile. That'd be a very nice touch.