it's easy to level your sights if you have and do the right stuff.
Of course you can, but how many people do.
How many people here (honestly) can say they check their scopes. Lets say your windage and elevation knobs are suppose to be 1/4 moa clicks.
ARE THEY, and are they at all ranges.
Take a tall target, about 4 feet tall. Set it up at 100 yards. Use a plumbob and draw a line down the center of the target and put the aiming point at the bottom.
Now zero at the aiming point. Move your sights 10 up, shoot again at the aiming point, move 1o more up and shoot again. Keep doing this until you run ouf of target.
Now check to see how far off the vertical line you are. Also check distance between groups. Bet their not constant, bet the groups arn't all on the verticle line.
Do the same thing with a horazonal target, left and right of center. Are they constant????
Everything is different, every scope or iron sight is different. You see this on high price scopes and cheap scopes.
This is another reason you can't trust BC programs, but your actual zeros. This is why I always preach the value of a well kept data book.
Yeah, maybe a bit off topic, but is it really? The OP was asking if a wind correction is linerer. It may be, but will our sights, or our shooting position, show this.
Bryan Litz (Berger Bullet Chief Ballistician) just came out with an excellent book, "ACCURACY AND PRECISION FOR LONG RANGE SHOOTING" that explains this much better then I can.
Litz uses what he calls a WEZ (Weapon Employment Zone) analysis showing the effects of such errors.
I highly recommend this book for anyone serious about their precision shooting. Its an eye openner even for an old has been like me who thought he knew what he was doing.