Seeing as there is an interest in the historical rifles I thought I would share what I know of the "historical" shooting techniques. I'm sure alot of this will be very familiar and very basic to the older shooters, but some younger guys might be interested how it was done back in the day.
Range estimation during the Vietnam period was a bit different than modern techniques, often a variety of manual range finding techniques were employed (the football field, the thumb technique and so forth). However a technological solution was sought with the adoption of the M40 rifle and the Redfield telescope system. The technique is straight forward enough, there are 2 ranging lines in the upper portion of the telescope and a "range tape" to range a target place the ranging lines and zoom the scope until the the two lines subtend the target from the top of the shoulders to the belt buckle.
Once the range is determined the sniper would apply the correct "hold" based on a 500 yard zero. He would also apply the correct hold for windage as well, based on chest width of roughly 18" as a guide.
Using this technique the sniper could rapidly and accurately (relatively, ranging is rather slow) engage targets from 100-600 yards.
Range estimation during the Vietnam period was a bit different than modern techniques, often a variety of manual range finding techniques were employed (the football field, the thumb technique and so forth). However a technological solution was sought with the adoption of the M40 rifle and the Redfield telescope system. The technique is straight forward enough, there are 2 ranging lines in the upper portion of the telescope and a "range tape" to range a target place the ranging lines and zoom the scope until the the two lines subtend the target from the top of the shoulders to the belt buckle.

Once the range is determined the sniper would apply the correct "hold" based on a 500 yard zero. He would also apply the correct hold for windage as well, based on chest width of roughly 18" as a guide.

Using this technique the sniper could rapidly and accurately (relatively, ranging is rather slow) engage targets from 100-600 yards.