.308" diameter bullets or .308 winchester chambering?

The mini-30 is chambered for 7.62x39 not .308 winchester
The 7400 is ok, but if you were wanting one, I' d buy one used- just about any gun shop that sells used rifles will have a full rack of them- they are good enough for big game hunting to moderate ranges, but not much else.

If you want an accurate and consistant autoloader, I' d get the Browning BAR.