I've been interested in guns for sometime now, shooting them learning about them etc. I don't pretend to be an expert but I know more than the average person. Having said that there is an area of firearms that I'm going to talk about in relation to the Flat Earth Theory, and that is long distance marksmanship.
Now again just a disclaimer I am by no means an expert on this subject so go out and do your own research on the subject, but I have learned a lot from talented marksmen. So, when firing a bullet at a target at a long range I believe 800+ yards there are a lot of variables that need to be calculated to make the target. Things like wind speed, wind direction, atmospheric pressure, temperature, the rifling of the barrel, and rotation of the Earth. When a marksman fires a round at a target a 1 ½ miles away the bullet is in the air for a long time. The bullet is moving independent of the Earth. This being said when the bullet reaches the target the earth would have rotated underneath the bullet moving the target along with it which may cause the shooter to miss their target.
Just recently there was a Canadian sniper that set the record for the world's longest kill shot. The kill was made from more than 2 miles away and the bullet was in air for about 10 seconds. Quite an impressive shot! This means that while the bullet was moving (for the sake of argument we’ll assume the ISIS member was stationary) the ISIS member was moving along with the Earth and this Canadian sniper would have needed to make the appropriate adjustments to the scope to counter this effect.
Zeroing a scope is when a marksman calibrated their optic (scope. Reflex sight, EOtech, acog etc.) so that the center of the crosshairs are accurate at a certain range. So, let’s say I zero in my scope at 100 yards, at a distance of 100 yards with 0 wind wherever the crosshairs are is where the bullet is going to be. Now let's say I’m zeroing my scope at 1760 yards (1 mile) I need to be conscious of the direction in facing when I zero my rifle. If I’m pointing North my zero is going to be off because the rotation of the Earth is going to cause the target to move and so when I zero my rifle and then shoot East the scope is calibrated to the rotation. Shooting east the target is moving away from me so there's some effect my not in the left right direction. Calibrating my scope pointing West is I’m told the best direction because the Rotation of the Earth is moving the target towards you not making a significant difference in the Left Right direction.
So, just something to think about. The Rotation of the Earth is of course very slight but it does exist when dealing with long distances. If something I’ve said is factually incorrect let me know below. Any counter arguments or the projectile vomit of a keyboard ninja is always welcome. PEACE.