Knowing where the shot's going to land the instant the rifle fires is an essential skill.
Developing the ability to call the shot not only improves the value of feedback you get from location of the shot on the target, it also helps build follow-through skills.
Articles on shooting technique usually focus on how to get the sights steady on the target. If you think about it, ideas on position, vision, breathing and so on ultimately result in finding a way to fire a center shot. Often, any such ideas and suggestions end with the all-important trigger break. However, I have found that what a shooter does after firing a shot--how he follows through--can have a big influence on that shot's location on the target.
"Calling" a shot is knowing the precise location of the sight the instant the rifle fired. This fundamental must be followed for each and every shot, live or dry. That goes for every shooting position, every event.
Although most shooters will focus more on calling shots in the standing position, it's even more important to work on this skill for the 600-yard prone event. It is here, though, where many shooters pay the least attention to calling their shots with exacting precision. When I say precision, I mean within one minute of angle; it can easily be half that with experience.
The shot call is a key element in the value of the feedback we get from the target and leads the way in all decisions made on sight corrections. One reason is that it's instant feedback. The feedback from the target (spotter location) is not instant; pit service takes time.
The call on a 600-yard shot is the first piece of evidence I'm going to use to determine what to do for the next round. If my call was a little this way or that way, then this gives additional feedback to use against the spotter disk location and against interpretation of the conditions.
In most circumstances, I know what I'm going to do on my next 600-yard shot before the target comes back up. That is the value of the shot call. I have my shot call in mind, and I've been watching conditions while the target has been down. When the target comes up, the spotter location is likely to be only a confirmation of the decision I've already made.
Without a precise call I would be behind the schedule I want to keep, which is always firing each round as quickly as is reasonably possible. I use my shot call, the spotting disk location and my current evaluation of conditions in combination to know what to do for the next round--but it starts with the call.
As a shooter focuses in training on improving the precision of his shot calls, he can establish a "call radius." The call radius is the amount of target area around the called location of the shot that he allows himself for error.
It's not possible to call every shot perfectly, and the call radius will vary with the event. My call radius for sitting and prone rapid-fire is approximately one-half minute of angle. At 600 yards it's a little less than that. For offhand, it's around a half minute, and in calm conditions it's closer to a quarter minute.
I know my rifle shoots within my best call radius, so I don't consider its accuracy as a factor. If your rifle doesn't shoot inside your call radius, then obviously the calls and results won't match as closely.
When someone can place shots inside the call radius, that builds confidence. The call radius can't get smaller until the shots are landing inside it. As more and more shots find their way inside that call radius, the shooter demands better and finer focus from himself, and the call radius shrinks.
Part of the value of focusing on shot calls is its help in developing follow-through. I can define follow-through most simply as "holding on" to a shot long enough to accurately call the shot. That means actually seeing the front sight jump in recoil. If a shooter doesn't see that, he's not seeing enough to truly note the location of the sight when the rifle fired. That is the minimum amount of follow-through necessary.
Some shooters blink when the rifle fires. That blocks critical input right when you need to see it. It may take a good deal of effort to overcome for some. Focus on seeing muzzle flash. You know your eyes were open if you see the front sight lift against an orange background.
Follow-through will also help you maintain the shooting position and hold through recoil, which has an influence on the quality of the hold itself. When a shooter decides that he's going to call his shots more carefully, the rifle movement pattern can improve, and putting forth effort toward extending the duration of follow-through can do the same
One tactic used by some shooters is keeping the trigger held back well after the shot has gone. The idea here, again, is that using this "trick" prior to pulling the trigger may result in a smoother trigger break. I don't exaggerate this in my shooting because I want to spend my time preparing for the next shot, but I do experience a somewhat more sustained follow-through on slow-fire shots. It is an idea worth trying, though, because of the aforementioned influence it can have on shooting technique.
Follow-through is not at all difficult to learn just as long as the shooter knows what he needs from it and can experience holding delays at different amounts. After some experience and experimentation he'll know how much is necessary, and also how much more helps him.