Sounds like you have a fouling problem, Bedding issues or a shooters error. I will explain because it happened to me also. With a powerful scope like you have you are looking at the first bullet hole. I know that sounds dumb but it happens. I have my target guns set up to shoot 3" high and right so i am not looking at the bullet holes. I am focusing on the target. Aim Small shoot small.
The other thing it could be is a settling problem or a bedding issue. If you clean and disassemble the gun every time you come back from the range when you go to shoot again the rifle has to settle down into its bed.
Try this. Next time to the range shoot the gun about 10 times. Clean it but don't take it apart. Wait for it too cool down about 30 min or so. Take a 22 with you and mess around at the range and then shoot it again. If it does it bingo the bedding is off. Then you may need to take it to a gunsmith(If they are still in CA
) and get it bedded. You can do it yourself but a Mini 14 is a little more tricky than a bolt gun.
The Mini's were know for erratic behavior a long time ago. I had one and the trigger group would fall out when shooting every once in a while(This was 20 years ago). I liked the gun but sold it for something that I probably don't have anymore either
If it was a scope issue it would be shooting all over the place and not be as consistent in its inconsistency as it has been(Does that make sense??) I hope so. A scope problem would have bullet holes moving around more.