I have a pre ban mini 14 and I am getting about 2" groups with it.
The twist needs to be high with the heavy bullets. My twist is 1 rotation in 7 inches so I can easily stabilize even the 75 grain Hornady Amax bullets. They wont fit in the mag though so I dont use them often. If you have a 1 in 9 or slower twist then you will want to stay with 55 grain and less for best stabilization.
I love my ruger for the up close coyote hunting
and it makes a wreck out of running jack rabits using plain ol' 55 grain pointed soft points.
Keep in mind that this gun was never designed to be a long range gun so it takes some work ($$$) to get it there. It was meant to be a utility gun specificly designed to handle farm and ranch work. i.e. coyotes, jackrabits, bobcats, some of our feathered friends and the occasional rustler [img]images/icons/wink.gif[/img] .
Other variations of the mini serve a better police/military/guard type function than the off the shelf mini but you should have lots of fun with it and messing with the loads a little will help your accuracy.
BTW My mini didn't seem to shoot consistently untill I had put about 2000 rounds through the barrel. Maybe I should have run some JB Bore scrub through the barrel.