Polish the bolt face. Debur the firing pin hole. That would be the first things I’d try. Then take a real close look at the extractor. Polish it. Maybe even put a slight bevel on it if you have to. Next, very carefully debur the magazine lips and polish. THen fire about 500 rounds through it using only military hardball ammo. Clean it real good and see if stops jamming. IF it does, but then still jams with hollopoints or softpoints, then you need to look at the chamber/feed ramp.
These are just the basics that work for all firearms in general. I don’t have any special specific knowledge of ruger mini ranch rifles.
Oh, also you should try half full magazine vs full magazine and see if that makes a difference. If it does, then you got a spring problem in your magazine.
Thanks for the info. I’ll see what I can do