Boomer has it dialed in. The MINI responds to the same tweaks as the M1A. Not surprising since it is based off it.
A match barrel WITH a good chamber is a HUGE aid in achieving more accuracy. The standard Ruger has a very long throat and less then match quality pipes. Similar to the military chambers used in AR's. All that leade allows the lighter bullets to bounce around before engaging the lands.
Crappy accuracy results. Cut a tighter chamber like the WYLDE or even a SAAMI 223 and things have a chance of working.
Proper bedding is critical. The orig style of action attachment is definitely 'milspec' and will rattle around all day long. Bedding the action AND the front ferrule properly locks the metal work in place.
Then there is the ammo. Like the M1A, you need ammo geared for the gas system and that usually requires components different from a bolt rifle.
Most factory ammo is designed to run in a bolt rifle or an AR. These usually shoot like crap in an old gen self loader. A gas adjuster is a huge aid.
Usually faster powders are used, adjusted to meet the needs of port pressure and cycle forces. These things tend to be very finicky on tuning. Small changes in powder have huge effects on harmonics. Just as easy to tune the load to the rifle as it is to use a part we can't get.
There are few companies in the US that tune the Ruger will excellent results. There are a couple of approaches but the results are the same.
MOA or better IS possible.
Tuning the trigger group should also follow similar tweaks to the M1A. Quite a nice pull should be possible.
Right now, I can access Butler Creek and Ramline stocks. For better or worse.
Shilen barrels are available and are designed to use the orig gas block. Many are reporting great results in the US.
Jerry
PS I am working on getting approval to import more stuff. Of course, nothing much is going to happen until after the new govt is installed and the new lay of the land is figured out. However, doesn't sound like there is going to be a ban on stuff. Just a bit more paperwork and hassles for the dealer.