Red Dot Zero from person to person

[Malarky112]

I’m just getting into the optics game. 
I purchased a Setup from friend and a much more experienced  and skilled shooter then me who had already sighted in the dot on the gun. 
 

When I shoot the gun it seems off a bit low left. 
 

Im switching from Glock to CZ so I know it could be me but it made me think. 
 

Is red dot zero the same for everyone? Once a gun is zeroed in it should be good no matter who is looking thru the glass, correct? 

[Nevadazielmeister]

35 minutes ago, Malarky112 said:

Is red dot zero the same for everyone? Once a gun is zeroed in it should be good no matter who is looking thru the glass, correct? 

 

Completely incorrect. Each person's eyes and their perspective to the sight to target is different. You can also do your own test by wearing a pair of glasses versus contacts and you will notice a point of impact shift. This is amplified with magnified optics. I shot my wife's Limcat while mine was in the shop and there was a huge difference and I had to account for that. I did not dare change her sight because then she would have been screwed up when she uses it. 

 

You really have to match the gun to you and you alone. 

[nhyrum]

Plus, everyone squeezes the trigger differently, which will move the point of impact a little.

Sent from my SM-G975U using Tapatalk

[Furrly]

Trigger squeeze is the difference or anticipating recoil 

[Malarky112]

27 minutes ago, Furrly said:

Trigger squeeze is the difference or anticipating recoil 

This is why I  hesitant to adjust the dot because with my glocks I had a tendency to shoot left.  I had mostly corrected it but wondering if I’m doing same thing with new gun. 
 

Learning a new gun and a new sight system at same time is rough. 

[Malarky112]

1 hour ago, Nevadazielmeister said:

 

Completely incorrect. Each person's eyes and their perspective to the sight to target is different. You can also do your own test by wearing a pair of glasses versus contacts and you will notice a point of impact shift. This is amplified with magnified optics. I shot my wife's Limcat while mine was in the shop and there was a huge difference and I had to account for that. I did not dare change her sight because then she would have been screwed up when she uses it. 

 

You really have to match the gun to you and you alone. 

This is exactly what I was wondering and I didn’t have much luck searching online. 
I also have astigmatism (wear weighted contacts) so I know the rd looks a bit different to me then to others. 

[nhyrum]

This is why I  hesitant to adjust the dot because with my glocks I had a tendency to shoot left.  I had mostly corrected it but wondering if I’m doing same thing with new gun. 
 
Learning a new gun and a new sight system at same time is rough. 

Adjust the sight for YOUR eyes and YOUR trigger pull.

Sent from my SM-G975U using Tapatalk

[Yondering]

2 hours ago, Nevadazielmeister said:

 

Completely incorrect. Each person's eyes and their perspective to the sight to target is different.

 

It's not about different eyes and perspective; the optic is still mechanically zeroed to the same spot. If you have irons cowitnessed it's easy to confirm this.

 

It's about different people shooting handguns to different POI because of grip, trigger control, stance, etc. The same thing happens with iron sights as well. It's the shooter's control of the gun that causes different POI, not a change in percieved POA. 

Edited November 8, 2019 by Yondering

[Amerflyer48]

Did a whole test of this when I got my Fiber optic sight setup with red,green, and black insert shot with and without prescription 

for me everything went into a 5” group at 25 yards composite and individual overlay targets (per setup red with prescript then fresh over target for red without prescription etc. ) show no noticeable shift 

 now between different shooters that may change also shooting style so we could safely say it is probably a combination so rezero it and run it like you stole it. 

[lstange]

Pistols recoil a little before the bullet leaves the barrel. How much the muzzle can rise depends on how hard you're gripping the gun. If the grip is asymmetric, that can add a horizontal component.

 

Bullet weight and muzzle velocity affect zero, too. Point of impact is usually higher with heavier bullets because they spend more time in the barrel. That is, at short and medium distances. After 25 yards or so you start to see the rainbow trajectory of heavier bullets.

 

Finally, parallax may be a factor. Shoot two groups, one keeping red dot near one side of the window and another keeping the dot near the opposite side. Chances are you'll see some difference in point of impact.

 

Trigger pull should have no effect, if you do it right.

[zzt]

I fine tune my dot zero from a rest, then adjust my grip and trigger pull to hit the same POI.  Doing it this way shows you what you are/were doing wrong.

[tyr264]

Had no idea that it could shift from shooter to shooter. Thanks for the information!

[Chrome308]

Grip, trigger pull and astigmatism can cause differences in POI for pistol shooters.  Rifle shooters the position of the shooter makes a small bit of difference, as does ammo.

Hitting low left though is the classic red flag of anticipation / flinch, especially if its more than just a little bit off. 

Anticipation is insidious, and can affect you in one gun, but not another. Or even one context but not another (shooting the same gun).  

[coryf]

My friends and I have noticed there is a larger difference in poi with a difference in height of the shooter.  Normally windage is the same but if the shooter is taller/shorter we see a poi shift higher/lower.  We were thinking the slight angle difference to the target with the dot over the bore axis caused a poi shift.  It definitely seems that zero is zero but for sure everyone pulls the trigger, sees a little differently.  I have borrowed one particular friends guns (both CO and open) and its spot on for me.  Other buddies have used my guns and its off for them.  Weird for sure.    

Edited November 13, 2019 by coryf

[GregJ]

On 11/8/2019 at 2:47 PM, zzt said:

I fine tune my dot zero from a rest, then adjust my grip and trigger pull to hit the same POI.  Doing it this way shows you what you are/were doing wrong.

 

This ^^^^

[Yondering]

9 hours ago, coryf said:

My friends and I have noticed there is a larger difference in poi with a difference in height of the shooter.  Normally windage is the same but if the shooter is taller/shorter we see a poi shift higher/lower.  We were thinking the slight angle difference to the target with the dot over the bore axis caused a poi shift.  It definitely seems that zero is zero but for sure everyone pulls the trigger, sees a little differently.  I have borrowed one particular friends guns (both CO and open) and its spot on for me.  Other buddies have used my guns and its off for them.  Weird for sure.    

 

I think this is a good example where correlation does not equal causation. You may have observed that the taller shooters in your circle shoot to a higher POI, but that does not mean those two things are related.

 

If this "slight angle difference to the target" was an issue, standing on a box or platform would cause the same result of higher POI, same with shooting at a lower target. I think most of us can agree that doesn't happen at any normal ranges or people's height variations. (We're not talking about shooting at steep angles up or down hill.)

 

 

Also this idea that people "see differently", as has been mentioned by a couple different people, is a myth as it relates to optics and iron sights. If you mount the optic or slide in a vise with the dot zeroed on a target, everyone looking through it will see the dot (or scope crosshairs) centered in the same spot, other than parallax error. Try this out if you don't believe it. The exception is people with astigmatism who see the dot as a blur, but even then one portion of that blur is still on zero.

Edited November 13, 2019 by Yondering

[Ssanders224]

1 hour ago, Yondering said:

 

I think this is a good example where correlation does not equal causation. You may have observed that the taller shooters in your circle shoot to a higher POI, but that does not mean those two things are related.

 

If this "slight angle difference to the target" was an issue, standing on a box or platform would cause the same result of higher POI, same with shooting at a lower target. I think most of us can agree that doesn't happen at any normal ranges or people's height variations. (We're not talking about shooting at steep angles up or down hill.)

 

 

Also this idea that people "see differently", as has been mentioned by a couple different people, is a myth as it relates to optics and iron sights. If you mount the optic or slide in a vise with the dot zeroed on a target, everyone looking through it will see the dot (or scope crosshairs) centered in the same spot, other than parallax error. Try this out if you don't believe it. The exception is people with astigmatism who see the dot as a blur, but even then one portion of that blur is still on zero.

 

All of this. 

[coryf]

The angle from a person's eye though the dot to the target can't effect Poi?I agree that from  the gun forward, zero is zero but I think the difference is from the eye to the dot.   If someone holds the gun a little lower, shooter is taller or shorter, ect. The line from the eye, through the reference point of the dot to the target might be different from person to person for a slightly different poi.   I'm not arguing, just an interesting topic.     For iron sights where there are two points of alignment it seems like poi shift would be to trigger control or simply where the shooter lines up the target.   A scope is also lined up with two points as well   the front/back of the tube.   

[Intheshaw1]

I would assume all dots are mechanically zeroed and it's the person's skill level that changes poi. 

 

The dot moves around in the window in relation to the person's sight line. If you can see the dot, that's where the bullet should go.

 

I trained extensively in the Army with red dots on rifles and sometimes a rifle would break during training and you would just borrow another and the scores rarely changed. I've also taken a new privates rifle who had trouble zeroing it and got it dialed in for him and he turned around and shot 40 out of 40.

 

I believe the same is correct for scopes as there are 2 pieces of glass, but only one crosshair. 

 

I could be wrong, but that's my experience with red dots and how it was explained to me in relation to rifles. I would think it would be the same for pistols as well.

[MemphisMechanic]

You are pulling shots low left.

 

Leave the gun alone and go practice with it until you can shoot it straight.
 

Sighting it in for your consistent error, as advised above, would work for now. But it won’t make you a better shooter in a hurry the same way that working on your grip and trigger control with a known-accurate handgun will.

[Slide4949]

I have always wondered how much you grip as to do with it, I would think a lot.

[CharlieD]

1 hour ago, coryf said:

The angle from a person's eye though the dot to the target can't effect Poi?I agree that from  the gun forward, zero is zero but I think the difference is from the eye to the dot.   If someone holds the gun a little lower, shooter is taller or shorter, etc.   

No, You can test this yourself pretty easily.  Put the gun in a vice or secure it someway.  Aim it at a specific point.  Now move your head around it up, down, left, right.  You won’t see any appreciable difference.

[lstange]

58 minutes ago, CharlieD said:

Put the gun in a vice or secure it someway.  Aim it at a specific point.  Now move your head around it up, down, left, right.  You won’t see any appreciable difference.

There is parallax, though. For example, Deltapoint Pro is off by about one inch at 25 yards if red dot is at the edge of the window.

 

But that happens regardless of how tall the shooter is.

[Yondering]

9 hours ago, coryf said:

  If someone holds the gun a little lower, shooter is taller or shorter, ect. The line from the eye, through the reference point of the dot to the target might be different from person to person for a slightly different poi.  

 

Others already answered this, but no, that's not how red dot sights work. As CharlieD said, mount your optic (or entire pistol, whatever) in a vise or even just set it on a table and look through the optic - the only movement you'll see between the dot and the target is a small amount from parallax. Other than that, wherever the dot is in the window, that's where the gun is aimed. 

 

Parallax error is a thing, but it's relatively small and does not correspond to different shooter's heights or anything like that. It's generally greater at the edges of the optic window, but with most decent optics the error is smaller than what most shooters can resolve freehand. Parallax error is the same regardless of the shooter as well. 

[coryf]

Thanks guys for the replies.   Interesting for sure.