I am not slamming the Mini-14. I just lament that it could have been so much better.
Accuracy is best determined by a known rifle. A Bolt gun is a good benchmark. If you are going to describe a Mini-14 as accurate, then I can describe an AK as a sniper rifle.
I spent considerable time, energy, and effort on making Mini-14 rifles accurate. I succeeded. But at the end of the day, they were no better than an AR-15. And after all of the effort, they were twice the price.
The bottom line:
Pick up a Mini-14. Pick your distance. Shoot. Evaluate your group. If you are happy, then it is a great rifle and don't listen to anyone else. And avoid all AR-15 rifles, because they are BAD. If you are not happy, then shoot an AR-15. If you like it better, sell the Mini-14 for a small profit and buy an AR.
Best advise I can offer.