Re: Mounting a scope sideways.....On purpose!?
Yes, rotating the scope so one know sticks out to left works fine. It can even work if one knob is sticking DOWN if you have short turrets/adjustment housing OR an offset scope mount, and even with side focus. Fat fingered people can read on...
MOST sights follow the convention of:
...........CLOCKWISE is LEFT or DOWN
(viewed looking AT the "knob")
(civie peeps and scopes, SERVICE Rifles in the CMP sense are BACKWARD)
For a SCOPE that's rotated, One adjustment/turret UP, one to LEFT
Things Stay the same for you as when mounted normally: The Adjustment towards the SKY/Up is ELEVATION, the adjustmet to the horizon is Windage. Then just use CLOCKWISE is DOWN or LEFT. DOWN if twisting SKY pointed turret, LEFT if twisting Horizon pointed turret. (Completely disregard printing on the adjustment)
The flaw in the Clockwise Rule is about 1/5 or 1/6 of CHEAP scopes (say $100 or less nowdays) vialate the rule for one or both adjustments. I've worked deer sightin days at the Range for 15 years. As time goes on it's getting easier to apply The Rule then squint at the adjustment markings! Also, about a third or more of these cheap scopes may be marked 1/4 In or MOA at 100 yards, but actually RESULT in 1/2 in or MOA per click at 100 yards.
The RULE is LESS Followed for pistols, something like 2 of 4 companies follow it, with 1 each violating it in one or more adjustments (S&W Colt Rugar High Standard)
"Red Dot" sights are all over the place in regards to "The Rule"
A few years back, a left handed friend showed up at the range the evening before deer season with his 12 ga slug gun. I was cleaning up the trash targets well after sunset and deep into twilight. The gun had fallen in the closet and the owner had "rotated" the scope tube to get a knob pointed Upward again, tightened the screws and panic dashed for the range. I moved behind him to spot. His 1st shot at 25 yards hit four feet left and low in the dirt. Wow. He was cranking desparately on the adjustments when I asked him why his scope was mounted wrong (adjustments on left and top sides) Amazing what your former elevation and windage adjustments of the scope are when they become your after rotation windage and elevation setting!