The Mini is a good gun when used for what it was desiged for. An inexpensive gun for farmers and ranchers to keep on their tractors or pickups for shooting varmits such as coyote and fox. They take a lot of dirt and neglect and still shoot, but have never been known as accurate rifles.
If shooting lots of rounds through them is your goal, they are not a good choice. Back in the 80's several LE agencies and even some smaller militaries tried them as a cheaper alternative to AR's. When used in that role they did not hold up well and were quickly dropped.