I apologize if this has been obvious to everyone here, except me. I've been struggling with the near wind vs far wind argument and have found the explanations regarding the higher impact of a near wind to be very deficient, while the arguments for the greater impact of a far wind have made sense. The problem is that people have tried to explain the greater impact of a near wind in terms of deflecting the angle of the bullet.
Anyone who has studied ballistics should understand that this is not true. The bullet leaves the barrel (or should) with such great gyroscopic stability that no amount of wind will change its orientation. Hatcher's study of bullets fired vertically showed that they returned to earth base-first, in the same vertical orientation that they left the barrel. They did not turn 180º and come back to earth point-first. Also, bullets striking the target at long range do so at pretty much the same orientation that they had when they left the barrel. This is one reason that bullets have slightly higher drag at long range than at short. So deflection is not a good term to explain it.
There was one spot in Miller & Cunningham's book where they quote Young who mentions "sideways velocity". It then struck me that you could look at wind and gravity in the same way. Gravity does not deflect the bullet, rather it imparts a downward velocity. If you had a magic pavement that could negate the effect of gravity and applied it to the last 500 yards of a 1000 yard range, bullets fired on this range would not stop "falling" when they reached the magic pavement. During the first 500 yards they acquire a downward velocity of about 175 in/s. They will retain this downward velocity for the rest of their trip, except for a small loss due to air resistance. So, a .308 bullet flying for 500 yards through normal gravity then 500 yards through zero gravity will still have a total drop of about 267", not just the 62" it acquired in the first 500 yards but this is still less than the ~400" drop it would normally acquire.
Using the same idea of "sideways velocity" I applied a "magic wall" or tunnel blocking the wind on the 2nd 500 yards to the problem and undertook the same Gedankenexperiment with my ballistic calculator and figure that a 10 mph cross wind in the first 500 yards imparts a ~51 in/s lateral velocity to the bullet. When the bullet flies behind the shadow of the "magic wall" the force that imparted the velocity disappears but the velocity is retained. Since the next 500 yards takes longer (1.17 sec vs 0.70 sec) than the first 500 yards, the total lateral displacement behind the wall is actually ~1.65 greater than the displacement in the first 500 yards.
All of this neglects a very gradual reduction of the lateral or downward velocity due to air resistance. if the bullet were able to fly over the "magic pavement" or behind the "magic wall" for a very great distance, it would eventually lose its downward or lateral velocity. Analogies of the boat traveling across a river don't work to explain this because the density of the water equals the density (displacement) of the boat and the very great friction of the boat moving sideways through the water will quickly absorb any lateral motion.
Anyway, thanks for bearing with me. I'm now convinced that the near wind has greater impact than the far wind but I had to work it out on my own.