I have a Mini-14 GB, 181-series. Have had it since 1980. I never thought it was inaccurate until I started reading this forum and PU (and the Ruger forum).
There were rumors that the early GB models got the best of the barrels off the production line (questionable) and also that the bayo lug and flash hider attenuated the stringing effect somewhat.
I don't hunt, and I don't shoot paper, and the only bench it has experienced is my workbench while I clean it. That is probably why I never considered it inaccurate...
But I wanted to be able to humanely dispatch a rabid coyote or fox out to about 250 yards should that unpleasant need ever arise. 250 yards is about the max clear distance on my property before I start running into woods.
I violated the first law by not verifying its inaccuracy before buying an AccuStrut but the reviews were pretty good and I fugured it couldn't hurt and would probably help. It was a challenge fitting it because of the bayo lug (I knew that before buying it) and once it arrived, I set about finding a suitable substitute that I could comfortably cut up without damaging the original strut. It turned out that two grounding rods that were sitting around - left at the farm by the previous owner (as well as a whole bunch of other "treasures") were the perfect diameters, so I cut one to the length of the original strut and began modifying. After a few tries (good thing there were two six-foot rods) I finally got a good fit and mounted it. As much as working around the bayo lug was a PITA, it actually helped to keep the strut from sliding (I didn't want to use the securing method of the screws into the gas block if I could avoid it).
I had also mounted a TRS-25 onto the funky mount that - aside from an UltiMak - is about the only option for mounting optics and had laser bore sighted it for 1.5" high at 25 yards (about the height of the TRS-25 above the bore).
Then I remembered...need a "before" before doing an "after". So I took off the strut when my nephew showed up for some shooting and also realized I probably needed to heat up the barrel some to test the stringing. After adjusting at a 25 yard target for 1.5" high (POA being 1.5" above POI and getting a decent three-round shot group, I adjusted to a 50 yard target (the range I wanted the rifle zeroed to). I made one or two minor adjustments for a decent 10-round shot group. This was all done in a prone position, resting on a cheap plastic Caldwell stand that bounced around a lot - requiring re-positioning it after each shot. Not exactly the best of test conditions...Not sure why I didn't use the bi-pod.
This was also done facing into the afternoon sun, so I had to set the TRS-25 setting to 7. Not sure how much MOA that makes the dot, but it was certainly more than five MOA.
To heat up the barrel, I did a 30-round and a 20-round mag dump in less than a minute (shooting creamer bottles at 50 yards and hitting most every one a few times), then popped in another 20-rounder and took aim at a new 50-yard target. I emptied the 20-rounder in just a bit over a minute, then went to check:
There was little to no vertical stringing (less than 2"), but there was some horizontal stringing (about 5" side-to-side). That was a bit of a surprise to me but at least I got the "before" condition, with a hot barrel. All twenty rounds hit the paper and within 5" of one another.
When I got around to tearing down my Mini to clean is when I noticed that the main screw that holds on the funky mount was very loose and the mount was very "wobbly". That was the only screw I hadn't "loctited"...I have since corrected that
Soooo, I'll have to go back out and try this whole "before" experiment again.
Bottom line, though, is it seemed pretty darn accurate (for my purposes) even with a hot barrel and a very loose mount, so there may be some validity regarding the better accuracy of the GB models.
BTW, my original quest to be able to humanely dispatch a rabid coyote or fox was solved with the purchase of a Savage Axis II in .223 Rem with a 3-9X40 scope that is rock solid, about 1-2 MOA. At $315 out the door, it was a pretty good deal.
Will provide an update once I get a decent "before" experiment done.