I read about 1" 5 shot groups at 100 yards in the old usenet group rec.guns in the early 1990s.
I tried all kinds of stuff.
In 2002 I finally got a 1" group.
A few weeks later I got a 0.5" group.
But don't think that one can always get tiny groups.
The wind changes between shots must be very low.
A good time to get that is at sunrise. The troubles is, many ranges open at noon, the worst time of the day.
I wish I had started with a 223 clean heavy barrel, 40 gr quality bullet and 16X scope on a windless day.
I would have saved a lot of years of effort.
The word 'forum" does not mean "not criticizing books."
"Ad hominem fallacy" is not the same as point by point criticism of books. If you bought the book, and believe it all, it may FEEL like an ad hominem attack, but you might strive to accept other points of view may exist.
Are we a nation of competing ideas, or a nation of forced conformity of thought?