“But it ain’t very accurate, due to loose fit of the bolt and such.”
May I suggest spending some time at the perfectUnion BBS?
The voluminous, and validated, methods of “accurizing” the Mini-14 are well discussed on that site.
AS an example, shortening the barrel, adding a brake, a trigger job, etc - all are extensively discussed.
The thin barrel seems more of a culprit on the inaccuracy issue than is bolt fit.
That's why Ruger has gone with a thicker barrel and better machining of the gas block/barrel fit, with the later Minis.
I have one of the older Minis, and with the right loads it is around 2 MOA. That's after working on the trigger and the gas block fit with JB Weld, not to mention glass bedding the action. That's not all that bad, and better than to be expected from the old thing. Still, despite all its flaws, I've had probably 2000 rounds through it and it is the ultimate in reliability. It has never jammed. Not even once. And that's 99% hand loads, not the expensive factory stuff that I don't afford.