Having started out, loooooooooooooooong ago with a gunshow SS Mini, probably sold off because the legs of the action over-rode the stock reinforcements, and so killing accuracy, I would never have gotten involved with the Mini.  Of course, back then, other semi auto rifles were a bit scarce, and some of them even more questionable than the Mini.  All of them were far more expensive.

To put it bluntly, way back in the day, the Mini was the affordable survivalist rifle of choice.  Rifles we have come to accept as common were unknown back then.  Or else unbelievably expensive, if one could find them in the pre-internet days.

Is this ringing a few bells with old-timers?  Anyone remember the pre-internet days of "Shotgun News" and other weekly bubs being the only sales offering, aside from your local gun store, who would be sure to wring the last cent out of any purchase, since they had np real competition?

As I have long said, as long as the previous owners of your Mini have not trashed the muzzle by improper cleaning implements/techniques, then even your pencil bbl Mini might be GTG.  In the event they did, have the barrel re-crowned by local gunsmith, or have barrel replaced by Ruger.  No other options, except bitching.  Personally, tired of that, since pencil bbls, like mine, or otherwise unmolested pencil bbls have been shown to be reasonably accurate out of the box, and even more accurate when gently massaged.

My OEM pencil barrel is a reasonably accurate barrel, although I have given it, down through the years, every tweak imaginable.  It's a GTG 2 MOA carbine at 200 yds, with decent ammo.  Better than that on some days.

Modern Minis are far more accurate, due to various mechanical improvements, and construction changes.

I would DEFINITELY caution any Mini owner to use a coated cleaning rod, and a suitable muzzle guide for same.  Same advice for M1, M-1 Carbine/M1A owners.  Same cleaning regime, same cautions.

I've seen loads of these firearms whose barrels--and accuracy--were ruined by improper cleaning implements/techniques.

Of course, this being an AR-based site, the Mini is universally trashed.  Might be unwise to do so.

In my personal experience, shooting against shorty ARs against my Mini-14, it was  pretty easy to goad the AR users into a bet that I, as a Mini-owner was confident of winning.  Can't prove a word of it, but the shorty AR guys who had no skills when shooting under pressure always failed.

The Mini was an acceptable firearm back then, but the Shorty AR owners were vastly overconfident.  Long on gear, but short on skills.  When put up against some serious money, and the arrogance of the AR owners, it was easy money in my pocket.

I paid for a lot of my Mini Upgrades by means of stupid AR owners.

Thanks guys!

OP, I congratulate you on reviving what was nearly a piece of junk.  In doing so, you have brought a tear to the eye of every gun-banner.
Some might question the financial wisdom of proceeding down your path, but I do not.  Sometimes projects have worth besides their monetary value.

I have spent a lot of time, effort, and a fair bit of money on my Mini-14, bringing a the pencil-barrel 185-series up to a reasonable standard of accuracy and reliability.  Fortunately, some uninformed shorty-AR owners helped quite a bit with the money part.   For your Range test, may I suggest putting the barreled action into a tight-fitting synthetic stock, and installing a barrel stabilizer?  These are both relatively simple things to do, and will make a considerable difference.  Depending on the rate-of-twist of your current barrel, be advised that the many rates-of-twist of the barrels seem to be "friendlier" to different weights of bullets.  I suggest investigating on www.perfectunion.com.  Of course, we here will be ready to help, if needed.

Best of luck to you, and thanks for making Diane Feinstein cry.

What is that white substance at the base of the ctg?  You definitely need to have the headspace checked on your Mini before firing it again.  If it becomes necessary to send it off to Ruger, make sure to remove the flash suppressor before doing so.