Letter Re: A Useful Rifle Zeroing Technique, and Effective Spotter Sighting Offsets

Dear Jim,
You brought up an excellent point when you mentioned zeroing weapons.
Everyone should know how to battle sight zero their primary defensive weapon (assuming adjustable sights). The procedure is as follows:
Move the sights all the way left (rear) and down (front). Count the number of clicks or turns necessary to reach the opposite extreme. Move the sights back to the halfway position and remember this number (it can be written on a laminated card in the butt/grip or even on the side of the stock). This is mechanical zero. It should be fairly close to actual zero and is the emergency default for any weapon you can’t sight in by fire or bore sighting.
Go to the range and shoot a tight, supported prone group at this setting. Adjust the sights as needed to get a good center mass group. Record how many clicks from mechanical zero this is, and memorize it.
Upon being issued or acquiring any similar weapon (AR, FAL, M1A, etc), immediately set to this setting. Even if you can’t range zero, you should be close enough to be effective.
It’s also a good idea to learn how to spot impacts, and how to have someone spot for you. This applies both to weapons that may be slightly sight-offset, and to long range shooting through wind or to ranged where trajectory shift occurs.

For sight offset, have the spotter place a small target (a tape disc or such. A thumbtack for really good shooters) on the larger silhouette. They should be able to “dial in” a shooter in a very few number of shots, by calling the distance.
For example, for a target 6″ above and 4″ left of center mass, the spotter would call, “Up six, left four.” Let’s say the shooter fires and hits an inch low and left of this position. The spotter would call that, “offset up one, right one,” and the shooter should estimate the new position, based on the fact that the weapon was off-target by that amount.
Practicing like this develops trust and rapport between shooter and spotter, trust in the weapon to perform consistently (And if it doesn’t, fix or replace it), and trust in one’s shooting abilities.
For spotting and shooting distant threats, the shooter concentrates on putting fire on target. The spotter is responsible for target identification and team security. It is important to maintain this division as much as possible to ensure effectiveness. Typically, the more experienced member of the team will spot. Everyone should be able to shoot reliably.
A shot like this proceeds with the spotter identifying the location and range with easy to find landmarks, then the target. “Straight ahead 320 meters. Lone pine tree.”
Upon sighting this location, the shooter should confirm. “Tree, Check.”
The spotter will continue with offset instructions. “Five meters left. Mutant zombie biker in prone position with rifle.”
The shooter confirms, “Target” or “position,” depending on whether they have seen the target itself, or have only identified the location in which the target is, and will be shooting to direction only. It is desirable but not necessary that the shooter see the target, as long as the spotter can, and the shooter can follow directions.
The spotter will give direction to wait, shoot, or otherwise.
Let’s assume on taking the shot, the impact is a meter short. The target moves and the spotter follows.
” Same target, new location, five meters right of tree.”
The shooter again confirms, “Target” or “position.”
The spotter corrects for the previous shot, assuming that the shooter aimed correctly. “Offset fire up one meter.”
It is important the spotter trust that the shooter is in fact aiming properly, and any miss is due to a combination of environmental factors. It is important that the shooter be aware of any errors they may have made, allow for those, and trust the spotter to give accurate data for offset. Guessing at it will yield poor results. Both must assume the other is effective.
Feedback is also important. If the shooter, for example, is consistently a meter short, the spotter can order, “Offset all shots up one meter.” Likewise, if the (local) shooter knows the tree is only 290 meters, he should relay that information so the (visiting) spotter can adjust his observations accordingly, to aid in locating less obvious landmarks (such as the “gray boulder, 275 meters” and the “depression in the field, 180 meters”).
I’ve been able to hit the previously mentioned thumbtack after dropping and misaligning a scope 6″ at 100 yards. I followed my spotter’s instructions to hit said thumbtack, which I could not see. At the time, my point of aim was over the silhouette’s left shoulder into empty space. It took one shot to determine point of aim, one to get within an inch, and the last to obliterate a .3″ target. This was due less to my shooting ability, than to my ability to trust and follow my spotter with his much more powerful scope and better visual position. It didn’t matter where the reticle was. It mattered where I hit.
This combination of skills saves ammunition and maximizes fire effectiveness in minimum time. – Michael Z. Williamson