Preface
I realize that some of the things I am about to mention are a bit more complicated or technical than I describe. To be highly specific would take a book length manuscript that I am not prepared or no longer qualified to write. (assuming I ever was, I suppose) It is provided to give a general understanding of differences between two shooting disciplines that have become blurred over the years. It not a how to manual for either one.
Purpose
From recent conversations I have noted a misconception that equates the largest part of military long range shooting to civilian long range shooting.
Although for personal reasons I am loathe to use the term "Sniper", when I say military long range shooters that is the military specialty to which I refer.
Not that there isn't some similarity, I however, would like to disspell some notions as it relates to long range target shooting and long range military shooting with scoped bolt action rifles.
There are four reasons why I think there is the confusion exists. The first is the similarity in customized and extremely accurate firearms used for both endeavors. Secondly there are a certain amount of crossover methods employed to hone skills and remain competent for both disciplines. Thirdly that some military long range shooters also very competitive in civilian matches leads to the belief that is the way it must done in the field. Lastly it seems that it is always the smallest part of a military long range shooters function that is presented in the action movies.
Objectives
The goal for civilian shooters is to repetitively hit the X at a known distance. The goal for military shooters is to take an enemy combatant out of the fight at varying distances. This may require a rifle to be X ring accurate but it is not accomplished by X ring shooting.
Shot cards/books
Serious civilian shooters and all military shooters keep a meticulous record of every shot taken with their firearm, ammunition and the conditions prevailing when that shot was taken. Military shooters must be more cognizant of elevation than the average civilian long range shooter as well. For civilians every shot on the range will be at the same elevation for the entire course of fire. For military shooters, not only the distance, the elevation could change from shot to shot.
Ammunition
Both types of shooters generally rely on one load and one load only.
Civilian shooters, as a rule hand load their ammunition to extract every last iota of accuracy out of the firearm/components as they possibly can. They will also verify their zero when any one of the components (primer/powder/case/projectile) is changed.
Military shooters sight (or at least used to) their rifles by the lot number of the ammunition issued. When a particular lot number is used up they will range test the new batch of ammo and only practice and field use that lot until it too is used up.
Note: Something simple like a different primer or lot number may not show any effect on accuracy at 100 yards. It takes distances of 300 yards and beyond for small changes like this manifest themselves. And they will. As a shooter you may not be able to notice a 1/8th inch point of impact difference in 3-5 shot groups at 100 yards, but that 1/8th inch difference translates to inches at 600 yards.
Accuracy
Firearms for both disciplines are highly accurate. The difference is in their utilization.
Civilian
Long range target competitors practice and shoot for score the smallest groups possible at a known exact distance. Long range competitors usually have the time to dope the wind, take test shots and preset the necessary "click adjustments" into the scope before shooting for score. Then all they have to do (for the most part) is put the cross hairs on the X and squeeze. Repeat as necessary as many times as necessary in the generous time alloted.
What I am saying is that a competitive shooter shows up to a 600 yard shoot knowing that for score each and every round he/she fires that day will be at precisely the same distance and elevation for every single shot.
Military
The largest part of military long range shooting is by nature mobile, supporting operational units in the field over varying terrain and distance. In field applications setting up to cut the X at long range is not a luxury military shooters are afforded.
That is not to say that they don't shoot for the smallest groups possible at distances on the practice range. They do.
What it means is that under changing field conditions they may or may not have the time to dope the weather and relative distance that shots might be necessary so that they can "click adjust" to a specific range for a single shot. Or even a number of shots. They will not have the advantage of test rounds to verify their rifles either.
Barring the time or opportunity to do any of that consider extensive knowledge of their particular firearm, ammunition and "Kentucky windage" to be the rule of the day.
Basic trajectory
The arc of trajectory with a 600 yard zero for a standard .308, 30-06 load will have the bullet somewhere in the neighborhood of 30 inches above the line of sight at it's highest point. A bullet aimed center of mass at midrange will have the shot pass right over the top of a normal person.
Note: To make that midrange hit at say 350-400 yards with a rifle zeroed for 600 the shooter would have to aim somewhere between the targets knees and feet to even have a chance at hitting it.
Military shooters (at least in my day) under varying field conditions and time permitting would determine a given range of distance that targets might present themselves, say for example 500 to 650 yards. Factoring in wind and elevation the scope is then "click adjusted" to point of aim at a median range of lets say (depending on the ballistics of the cartridge) 600 yards.
This median range adjustment (if possible) creates a fire zone in which the bullets flight path, in that zone, is no more than 15 inches above the line of sight and no more than 15 inches below the line of sight. (500-650 yards)
As I noted earlier to remove an enemy combatant from action does not require X ring shooting. Yes it requires a firearm capable of it even though it is not the mission of military shooters to specifically kill the aggressor. If they die as a result of the shot it is only a side effect not the stated goal.
Quartering the target
The average human torso is about 30 inches from the top of the head to bottom of the groin.
Remember the 15 inches above/below I noted? See the correlation?
When a target presents itself anywhere in the "predetermined zone of fire" all the shooter has to do is center the cross hairs so that there is an equal amount of target in each of the four sectors of the scope (quartering) and squeeze the trigger. Repeat as necessary as fast and often as necessary in the limited time available.
The result, if all things are as they should be, is the target will be impacted, not behind the ear as too many now days believe, somewhere between the top of the head and the groin. Mission accomplished.
This is what the largest part of military long range shooting is about and has no real similarity to civilian shooting.
The Small Part
Another much smaller part that does have some similarity to civilian shooting is when a military shooter is assigned to eliminate a specific target. Whether it be a carbon based life form or a piece of equipment, all of the precision that civilian shooters strive for will now come into play.
Assignments such as this can generally dictate in advance, a pre-selected shooting position, the exact distance to the target and elevation.
In instances like these the shooter may even be able to practice the shot on the range duplicating the distance and elevation. In these rare events the rifle can then be pre-zeroed for that exact shot or shots thus allowing for the same precision at which civilian shooters excel.
Of course this smaller part is the one most often portrayed in all the action movies. No wonder we think that is all there is.
Yes there are some minor similarities between the two disciplines but the differences are major. Hopefully this explained that.