2x red dot, two users, two very differnt aim points

[TDL]

Friends,
I have a 2x truglo red dot on a 10/22. When zeroing at 75 feet my son and I are each alternately off by 8".

By that I mean if he zeros it on clamped bench rest he can do an very tight group in bullseye and if I shoot it at his zero I have a very tight group 8" up and to the right at 01:30. If I zero it on clamped bench rest, then his group is 8" at 07:30.

I don't think this is from poor trigger pull as this is not happening with iron sights on same firearm. We get looser groups but average in the bullseye on iron sights

Has anyone seen anything like this phenomena? Is it likely one of us is doing something wrong? we are obviously zeroing well since each of us does well with their own zero.


Of course I could just buy another 10/22....

[gwpercle]

It is a common thing. People are different and their eyes are shaped and spaced differently, holding and mounting the gun in slightly different ways and I'm sure there are a dozen other different reason's for it. That's why you should never have another person sight your rifle in for you. It may not be where your eyes look . You are correct in noting it shows up more with optics and especially with magnified red dot. Not so much with conventional open iron sights, and receiver mounted peep sights.
But all bets or off when it comes to optics , you just have to sight them and try and see if your points of impacts coincide.

This is the perfect excuse to buy that boy (or yourself) a new 10/22 and sight. Every boy deserves his own real rifle.

Gary

[Bart B.]

It's a very old myth that different eyes see through sights different ways. All eyes see the same through sights. The light rays going through sights are the same for all.

Zeros on arms change with shooters because we all hold and shoot them differently. Trigger pulls aren't equal across all people. While the bullet goes down the barrel, it moves differently depending on how it's held.

[NoSecondBest]

Many of the lower priced red dot sights have a LOT of parallax, a LOT. Your cheek weld on the gun can be different enough to cause this problem. You can check the sight for parallax easy enough. Simply put the sight on a table or flat surface and put the dot on a target at 24 yards. Then move your head around while looking at the dot and the target. Does the dot stay on the target? If not, you have parallax.

[Theohazard]

NoSecondBest hit the nail on the head. Sure, it is true that different people hold the rifle in a slightly different way, which affects the bullet's point-of-impact slightly and therefore the zero ends up being slightly different for different people. But there's no way that this would account for an 8" difference at 75 feet. Not even close.

No, the reason for the 8" difference is that TruGlo sights have a HUGE amount of parallax. Unless both people are positioning their eye in the exact same place behind the sight, the reticle is going to appear in a different place for each shooter.

This is one of the reasons why people invest in higher-end sights like Aimpoints and EoTechs; they're virtually parallax-free, which means that no matter how you move your eye behind the sight, the dot stays in virtually the same place instead of moving around like on a TruGlo.

[Blindstitch]

I have a Truglo that I put on a 22lr for Melody. I zeroed it and I was shooting good groups. Now Melody is a Lefty and I'm a righty. She shot it and had good groups to. Just not where I was.

Cant remember how it went but I ended up zeroing the rifle between the two groups so when I used it the groups were a hair left for one and a hair right for the other.

It didn't take long before frustrations lead to a scope being mounted.

[Double Naught Spy]

If you can bench the rifle and look through the sight at a target and move around behind the scope and see the dot cover different areas of the target, then you have a good idea of why when two different people mount the same scope, they don't have the exact POI when firing because they don't have the same POA when pulling the trigger.

[g.willikers]

It's understandable that a scope would do that.
Open sights have two aiming points, scopes have but one.
Dot scopes are neat and very helpful, but there's drawbacks to everything.

[Mobuck]

A $400 AimPoint won't have parallax issues. What you found with your TruGlo is typical of economy of manufacture. I'm not saying that in a derogatory sense, but it's just the way it is.

[Double Naught Spy]

A $400 AimPoint won't have parallax issues. What you found with your TruGlo is typical of economy of manufacture. I'm not saying that in a derogatory sense, but it's just the way it is.

And yet, here is a video that shows you that where you line up behind the scope DOES change your POA. As the camera moves around behind the scope, you can see the dot's position on the 'Buddha' target swing L-R and H-L.

https://www.youtube.com/watch?v=RaE-1UjrV5Q

Same here...
https://www.youtube.com/watch?v=DRHlBQyAKj4

[NoSecondBest]

Aimpoints and scopes are two different animals. You're comparing one to the other and you can't do that.

[Jim243]

Undoubtably one of you are wearing contact lenses or prescription glasses.

Jim

[FrankenMauser]

Undoubtably one of you are wearing contact lenses or prescription glasses.

That was my initial thought, as well.

Parallax and other factors are certainly a possibility, but corrective lenses can have the same effect.

When I change between my primary glasses and my backup glasses (different lens shape), the POI shifts 2-5" for most optics. Even removing the glasses and focusing a scope's eyepiece to compensate will result in a POI shift.

[Double Naught Spy]

Aimpoints and scopes are two different animals. You're comparing one to the other and you can't do that.

Considering they are supposed to be parallax-free, I am not sure of your point. The issue happens with some scopes and it happens with Aimpoints and other red dot optics as well, some more so than other.

Besides, the statement was specifically made that it would not happen with an $400 Aimpoint and my post was to show that it most certainly can.

And oh by the way, Aimpoint makes scopes as well. So Aimpoints and scopes are sometimes the exact same animals.

[NoSecondBest]

You're getting very defensive. You did compare a red dot with a scope in your post. You're still wrong.

[Mobuck]

My reference was specifically concerning the AimPoint red dot sights(both 1x and 2x{more likely to show parallax issues}). We've used them in some very unorthodox ways(assisted sighting device for blind shooter) with universally positive results.
I have a 2x TruGlo and it DOES display parallax induced POI variations.
The OP specifically stated the problem was noticed using a 2x red dot.

[Double Naught Spy]

Whether or not two particular optics are compared is not relevant to whether or not one has a parallax issue, NoSecondBest.

Red dot optics can have this problem
Red dot scopes can have this problem
$400 red dot optics and red dot scopes can have this problem, specifically the Aimpoint noted as I noted above.

Some scopes have a parallax adjustment, some do not. The Truglo 2x does not and is reported by reviewers to have parallax issues. Two different shooters most definitely may be getting two different POI as a result.

There you have it.