From Seven-Shooter: "I could have sworn that I read somewhere where some of the older rear sights were 1.5 MOA per click."
This is true, for Standard Model Mini-14s, such as my 186 series; Ranch models had different rear sights. The OEM sight adjustment "wheels" have 4 slots, both windage and elevation, which works out to 1.5 MOA adjustment increments. No doubt this has led to a lot of frustration amongst owners who assumed the adjustment increments to be 1 MOA.
The fix for this is to order new sight adjustment "wheels" from a vendor, and to use a Dremel tool, with cutting wheel, to carefully cut intermediate notches into the elevation and windage wheels. You will need some "Jeweler's" files to complete the job, and some "try-and-fit" will likely be required. Although the specific Ruger rear sight tool will not work quite as intended, since there are more notches, it will still work, but with a little repositioning. Far better than a bullet tip, which buggers-up the bullet tip, causing flyers Strongly suggest obtaining correct rear sight tool for Minis that require it.
Not as slick as the replacement rear sights for early-model Minis, but a lot less expensive. In practice, and given the type of rifle that the Mini was intended to be, I have found my modified rear sights to be entirely adequate. For the most part, factory Mini rear sights are "Set-and-Forget" units, and intended for Field use, not the target range.
My main sighting system is based on an Ultimak scout rail, and some sort of optic, be it Scout Scope or Reflex/RDS. Many experienced users of the Mini-14/-30 have gravitated towards this set-up, and I have followed their good example. YMMV.