I had an interesting discussion with some guys about weapon zero today and the issue of “individual zero” vs “weapon zero”. What I have learned/read over the years is that scoped guns are different from iron sighted guns and both are different from red dot/holo sights.
- On magnified optics (Sniper Rifles), scope parallax can cause differences in individual zeros depending on how the shooter mounts the gun…his distance of eye from scope..etc.
- In a perfect world, where all of us use the exact same sight alignment/sight picture, all shooters would be “zeroed” with properly adjusted iron sights. Because there are differences in how we “hold” on target and how we center up irons there are going to be small differences in zero. But as long as they are “close” those differences are not drastic within realistic ranges.
The Army FM 23-9 states that “When standard zeroing procedures are followed, a rifle that is properly zeroed for one soldier is close to the zero for another soldier”, this allows soldiers to accurately shoot with another soldiers rifle if he needs to pick one up.
Zeroing is primarily about aligning the guns sights with the barrel..taking individual differences in sight picture into account to fine tune.
FM 23-9 says:
“the similarity of individual zeros should be emphasized instead of the differences.”
“There is no relationship between the specific sight setting a soldier uses on one rifle (his zero) to the sight setting he needs on another rifle. For example, a soldier could be required to move the rear sight of his assigned rifle 10 clicks left of center for zero, and the next rifle he is assigned could be adjusted 10 clicks right of center for zero. This is due to the inherent variability from rifle to rifle”
Which is something many people don’t realize. When I was a young private I thought for a long time that my “zero” was MY zero and that if I dialed it in on any M16 I was issued I’d be GTG. The fact of the matter is that zeroing is really about aligning the SIGHTS to the gun…not the shooter. If we all held a gun the same way and used exactly identical sight pictures/alignments a zero would be universal. Individual zeroing is really just a “fine tune” when proper marksmanship fundamentals are applied.
- Red dot sights/holographic sights do not rely on sight picture or eye relief. If a RDS is properly adjusted so that the bullet impacts where the dot lays, that sight is zeroed for all shooters who use that weapon. Any variation with a RDS is based on the shooters breath/trigger control. Of course the dot only represents “zero” at 2 points of the bullets trajectory. With our 50 yard zero that should be at 50 and approx 200 yards. The round will strike below the dot when closer than 50 yards and approx an inch to 1.5 inches above the dot between 50 and 200 yards and then drop off past 200.
Of course time and a beating may loosen up the Aimpoint tubes causing a Zero shift.