If our weapon systems really do hold zero, why do we start every qualification with half a day of zero confirmation? And why do the vast majority of shooters have to make adjustments each time?
We've been hiding a zero retention problem by adjusting zero prior to qualifications and live-fire training days.
The Army's SWEAT model, which was developed by the Maneuver Center of Excellence (MCoE) at Ft. Benning, GA, is useful for understanding combat weapons as a ‘system of systems’- and for understanding the elements involved in establishing and maintaining zero. Within the SWEAT framework, the individual weapon ‘system’ is comprised of: Soldier (or shooter); Weapon; Enhancements (i.e. optics and mounts); Ammunition; and Training.
There’s obviously no magic in this model- and there wasn’t intended to be. But it serves as an excellent reminder that achieving effective hits on bad guys involves more than just a rifle or an optic; it requires proper calibration of each of the elements of a fairly complex system. This is important, particularly since we have a tendency to look at one or two components of the system (typically the gun and sights) in isolation.
So, what does SWEAT have to do with zero? A lot. Zero is traditionally defined as the alignment of sights so that point of aim (POA) equals mean point of impact (MPOI) at a specified distance. That’s technically true. Zero isn't just about sights, though. It's about getting ALL of the elements of SWEAT aligned and calibrated. A perfectly zeroed weapon, for example, will be suddenly un-zeroed if the shooter changes his/ her cheek weld. So, professionals must buy a high-quality, battle-proven optic and a solid mount- that’s incredibly important. But that’s not the end of our zero retention concerns.
Zero is the glue that holds the SWEAT elements together. It's about getting ALL of the components of SWEAT calibrated to each other. If any one of the components changes or moves, zero is lost… AND WE MISS.
If you’re reading this you probably know better. A ‘minor’ one inch zero adjustment on the 25m zero range means that, if the shooter had been called on to use the rifle before the adjustment, a perfect sight picture and flawless fundamentals would have yielded peripheral hits (that may not stop the threat) on a fully-exposed, squared-up bad guy… inside of 100m. Bad guys using cover or further away would have been missed entirely. Maybe this is why the M4 ‘isn’t lethal enough’?
The more we improve the components of SWEAT, the more dangerous loss of zero becomes. In fact, it reverses the overmatch that our superior equipment and training provide us… and puts us at a distinct disadvantage.
Under stress, a skilled shooter with good equipment will place the dot on the threat and deliver a relatively tight shot group. He’s done so enough in training (after adjusting zero) that he expects hits. BUT… if zero is off, the result will be very consistent misses. A terrorist with an AK, by contrast, may spray rounds in a 24 MOA cone (so zero is not important for him)…. but the law of probability says that one of those sprayed rounds will eventually find its mark. Meanwhile, we’re still shooting our tight group of misses. When our zero is off, even a little, the precision of our weapon systems works against us.