Any pencil barrel Mini will benefit from a two clamp Accustrut (with the "dimple" option).
Before I switched over to the Mini-30, my last Mini-14 was a 196 series.
Threading it for and adding a flash hider, a smaller gas bushing and buffers, trigger job and Ultimak helped, but what helped the most was the addition of the Accustrut.
All the mods got it down from 3 1/2 MOA to 1 3/4 MOA.
Handloading heavier Sierra match bullets got me very close to 1 MOA.

I no longer become obsessed with trying to make any Mini a tackdriver.
Do what you can and if your Mini ends up a 2 MOA carbine, enjoy it, you are doing pretty well.
There shouldn't be any difference in chamber depth or tightness between Minis, except of course the Mini-14 Target.

 

I’m not sure the long chamber is the entire issue. Plus with mag length you can do so much. My 581 16” has delivered moa indoors at 100 yards. (55 gr FMJBT handload) So I’m thinking the heavier barrel has merit and the lighter barrels with accurizing devices does as well. Jmho
But yeah, they aren’t marketed as tack drivers.
“Proper tool for the job”.

 

I looked online asking the same question about a #196 series, and it was mostly favorable. The #196, having a 1 in 9 twist barrel, is a different production run, being built after 2000 and up.
My #188 (1992) has the 1 in 7 twist barrel, and is right in the middle of those Minis with the most issues with accuracy. The deep cut chamber is just another example of the sloppy tolerances found at that time.

There is no way to try and load to the lands, cartridges being limited by the size of the magazine.

Another post would be needed to explain all the changes, upgrades, repair of defects, and my inventions which have been added to my #188, bringing it up to the acceptable level of performance it has today.

 

If you have reliably measured the chamber of your Mini, and have concerns that the chamber is "long" from the factory, have you considered sending it back to Ruger? Naturally that will mean replacement of substituted parts of any type with OEM parts-- a PITA. IDK if this type of Warranty Serice is still available from Ruger for your particular Mini.

OTOH, a replacement of the barrel, and careful head spacing may be available from ASI, although at some cost to you.

 

As a longtime fan of the Garand and M1 Carbine, I was excited to get a beautiful stainless, wood stocked Mini14 and its 5.56 load.
Unfortunately, its performance didn’t live up to its looks.
Had few jams, something I’m not used to with my Garand or Carbine. Now, I didn’t expect a “tackdriver”, but I sure didn’t like the basketball sized groups it shot at 100yds. By comparison, an AR I put together as cheaply as possible(less than $300), complete with used ban-era A1 16” carbine upper, shot a palm sized 10rd group, standing offhand, at the same range.
I moved the Mini on. Still have the M1 Carbine, which is also much more accurate than that Mini.
I love Ruger, but the Mini could be so much better.

 

While I appreciate the suggestions, I don't want to derail my own thread and discuss the #188. I would like to confirm RIBob's point; I did call Ruger C/S and talked about what could be done. They readily offered to take a look at it and stated that if the chamber was cut as I stated then they would issue a discount on the purchase of a new Mini. Also, Ruger does not have replacement barrels for this series rifle.
That's a fair deal considering the Mini was made in 1992.

Then there is the problem of returning a heavily modified Mini back to Ruger. Ugh.

Purchasing the #196 is probably easier than going through a new barrel replacement. That's why I'm interested in that series Mini.

 

Ruger offering "discount" on a modern "heavy-barreled" Mini might be worth considering, since "heavy-barreled" Minis are generally more accurate than "Pencil-Barreled" Minis.

If you're certain that your Mini was mis-made, then probably the best alternative, least cost open to you.

All this depends on the price, but probably least cost from Ruger, given Warranty concerns.

Personally, I'd send the Mini off to Ruger for upgrading/repair and eat whatever Ruger charges.
Ruger is often very "reasonable" as concerns Warranty charges.

Better than a "Safe Queen" which is useless. YMMV.

 

I wanted to share this info about Ruger's C/S, as they were really understanding and made a decent offer. It wasn't like this way back in the 90's. They've changed for the better.

 

Great info! Thanks for the report.