I own three of them, a 180 series Mini 14 (middle),184 Series Mini 14 (top) and a 187 Series Mini 14 Ranch Rifle (bottom):
They are all different horses for different courses and they all evolved their way to what they are now.
The 184 series had been cut down to 16” by a prior owner, probably in an attempt to improve its 5 MOA accuracy. It apparently didn’t work, which may have been why he sold it. A SOCOM sized AccuStrut and Choate Browning style flash hider tamed the barrel harmonics, and a .045” gas port bushing solved the over gas and excessive slide velocity issues, while a Shok buffer also helped reduce the vibration issues. Along with a Tech sights RR200 rear sight those changes improved the accuracy to 1.5 MOA 5 shot groups at 100 yards, using Hornady 55 gr FMJBT bullets at M193 velocities.
It originally had a wood stock and the original fiberglass handguard.
I put it in a new stock, with a wood hand guard and while I liked the looks barrel cooling was an issue.
I switched to a Choate hand guard to get the slim line feel of wood, but with better cooling.
When Samson started making a copy of the Ruger folding stock it was a natural fit for a 16” Mini 14. I initially went back to the wood hand guard because it just looked really good. However I installed the Accuracy Systems aluminum handguard that is on it now in the first picture in the post, again due to barrel cooling issues.
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The 187 Series Ranch rifle was surplus from the NC Dept of corrections and came with an enormous combination flash hider, front sight and bayonet light. It weighed almost 8 oz. The scope and rings didn’t come with it, but they obviously had it scoped as the giant muzzle device caused it to shoot 8” low at 50 yards even with the rear sight fully bottomed out But it shot a 3/4” group at 50 yards with that big hunk of metal.
I gave it the same accuracy treatment as my 184 series Mini 14, along with a Choate ventilated hand guard and got the same 1.5 MOA 5 shot group accuracy at 100 yards.
I bought a set of Ruger rings, scoped it and gave it the walnut stock as the longer length of pull was better suited to a scoped rifle. Since high rates of were not an issue in its intended role, I also gave it a wood hand guard. It’s a wonderful handling rifle with suitable deer and predator rifle accuracy in a nice, non scary wood and walnut package.
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I bought the 180 Series Mini 14 as I always wanted one. It was a surprise on the range as it shot well in box stock condition at 3 MOA. I put a slip on flash hider on it for a bit of muzzle weight to see if it helped the harmonics and it shot 2 MOA.
So I installed a Choate Browning style flash hider, partly for the improved front sight, got the same 2 MOA accuracy and left it alone otherwise. I noted the gas port size was .052” compared to .080 on the 181 and later series mini 14s so it wasn’t over gassed like the later Mini 14s.
After shooting a 180 series, I could see why Jeff Copper gave it his endorsement after testing a 180 series Mini 14. It has the same delightful handling as the M1 Carbine but with 18” barrel 5.56x45mm NATO performance and acceptable accuracy.
After taking it apart and comparing the 180 series to the 184 series it was obvious that Ruger had substantially beefed up the bolt and slide when it developed the select fire AC-556, along with a modified stock and has block to accommodate the deeper slide and gas block. Unfortunately they redesigned the 181 series Mini 14 to use the same heavier parts.
Between the increased reciprocating weight and over gassing the rifle, the accuracy on the 181 and subsequent series suffered significantly.
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With the 580 series Ruger retooled to tighten up the tolerances and in the middle of the 580 series introduced the heavier tapered barrel. Between those two changes the 58x series rifles shoot 2 MOA out of the box, finally getting the accuracy back in the same ballpark as the 180 series.