of course assuming those great scenarios wherein the receiver is true, and barrel is true--ie., both running along the same axis, and base mounting holes correctly aligned/bored, scope free from what i call "reticle cant" within the tube, etc.


i view it as an issue that is based upon "Foundation":

aligning the base or bases so that they are oriented with the receiver/barrel centerline (often, two piece bases are off-line with respect to each other--an oft missed gremlin);

setting the rings so that they are aligned with each other, while in addition, aligned parallel with the "centerline" of the barrel;

setting the scope so that the vertical crosswire is aligned with the vertical/central axis of the firearm;

keeping the vertical crosswire vertical in orientation while firing...

square, level, plumb, and true...

coming from a construction background--it's a lot like building a house. you start with square, level footings--straight, square, level, and plumb foundation--and many happy things proceed from that. a mistake in the chain and its an "agony of errors" to try to correct for...

John, an interesting take on Tubbs' set-up of his rigs. i talked with him about some of this about 4 years ago. unfortunately--as Robert R. once said, "most of us folks ain't Tubb", which is why square, level, plumb, and true is best/solid for most all individuals...

while i've messed/tinkered with these things most of my days--there's always something new to learn/discover, which can humble one to near amateur status all over again...

all learning is like a funnel:
however, contrary to popular thought, one begins with the the narrow end.
the more you progress, the more it expands into greater discovery--and the less of an audience you will have...