Semi- Auto accuracy

[Radmd]

I do not want to start a flame war!!! I have owned numerous semi autos SR9 T, NM M1A1, FALs and mouse guns(AR15s). Most of which have come and gone to people with more money and sense than myself. Of all of these my mouse guns were the only ones I have seen consistantly shoot true MOA or less (some much less). Opinion on the following
1.To build a hyper accurate 7.62 which platform? Please address the following issues with each. Free float barrel, pain in the butt with M1A1 easy on others. Press in vs screww in barrels G3 vs FAL. Scope mount capability. Dust cover vs receiver. Trigger seem to be in favor of M1A1.
2. Your opinion on how to solve the above problems with the different types of platforms. ie rock solid scope mount for FAL? G3 vs FAL vs M1A1 vs AR10.
3. My analysis seems to indicate the AR10 would be the way to go (no stones please only words). Having never owned or even shot one that comes from just paper (which is usually deceiving). Easy scope mounting to the receiver easy to free float etc. The only draw back seems to be cost and the fact I like to build rifles whenever possible.
Like I said not trying to start a war just learn something.
Rad