Red Dot Pistol Sight question

[Pasanova]

Several co-workers have purchased Glocks and Sig p320s with RMR and other slide mounted red dot optics. We are in the process of having pistol red dots approved as an optional item. I have been shooting iron sighted pistols for over 35 years and use them pretty well. I've tried a few of the red dot equipped pistols and found an issue that I'm hoping someone here can help me with.

Say I have a Glock 17 MOS with a Trijicon RMR2 and suppressor iron sights. The RMR2 and iron sights shoot point of aim/impact. My target is a 3x3 inch card at 15 yards. I purposely place the left edge of the front sight against the leftmost edge of the rear sight. This means the bullet will impact to the left and completely miss the card. While maintaining the above iron sight alignment/sight picture, I place the red dot on the center of the 3x3 card, I miss the target to the left every time, even though the red dot is in the center of the target.

What am I missing?

[Kirk]

Several co-workers have purchased Glocks and Sig p320s with RMR and other slide mounted red dot optics. We are in the process of having pistol red dots approved as an optional item. I have been shooting iron sighted pistols for over 35 years and use them pretty well. I've tried a few of the red dot equipped pistols and found an issue that I'm hoping someone here can help me with.

Say I have a Glock 17 MOS with a Trijicon RMR2 and suppressor iron sights. The RMR2 and iron sights shoot point of aim/impact. My target is a 3x3 inch card at 15 yards. I purposely place the left edge of the front sight against the leftmost edge of the rear sight. This means the bullet will impact to the left and completely miss the card. While maintaining the above iron sight alignment/sight picture, I place the red dot on the center of the 3x3 card, I miss the target to the left every time, even though the red dot is in the center of the target.

What am I missing?

If your dot is correctly sighted in and the dot is over the target, you will hit the target if you do your part. The bullet will go wherever the dot is if sighted in.

[joshs]

I'm assuming that by "maintaining the above iron sight alignment/sight picture" you mean that you are still aiming off the card with irons and then moving your head behind the gun to have the dot at the far edge of the window in the center of the card. If not, I don't think I understand how you could move the dot while maintaining the same sight alignment/sight picture with your irons.

Red dots still have parallax, some more than others, but I haven't used one that would allow for the type of aiming error that you are getting (seemingly over 10 MOA).

When zeroing the dot, did you zero it in the center of the window or attempt to zero it to the irons?

If you shoot a group with the dot centered in the window on the same card, do you have any similar issues?

[Pasanova]

I'm assuming that by "maintaining the above iron sight alignment/sight picture" you mean that you are still aiming off the card with irons and then moving your head behind the gun to have the dot at the far edge of the window in the center of the card. If not, I don't think I understand how you could move the dot while maintaining the same sight alignment/sight picture with your irons.

Red dots still have parallax, some more than others, but I haven't used one that would allow for the type of aiming error that you are getting (seemingly over 10 MOA).

When zeroing the dot, did you zero it in the center of the window or attempt to zero it to the irons?

If you shoot a group with the dot centered in the window on the same card, do you have any similar issues?

Joshs...I'm referring to exactly to what you spoke about in your first paragraph. If one's presentation/grip is poor it is relatively easy to miss a small target. What are remedies to this?

[joshs]

Joshs...I'm referring to exactly to what you spoke about in your first paragraph. If one's presentation/grip is poor it is relatively easy to miss a small target. What are remedies to this?

Again, I don't think you should be able to induce the amount of parallax that you are getting with a quality red dot. Something may be wrong with either the optic or how it is mounted to to slide.

As far as how to deal with the issue of parallax more generally, it's the same as using an RDS on a carbine or, to an extent, reading iron sights. You still need to understand the aiming device and how it affects what you need to see to make a given shot. If the dot is buried all the way to the side of the window, trying to make a shot that is a very low probability shot (given shooter skill, mechanical accuracy, and ammo) probably isn't going to work. However, I think that this is also something that is very hard to do unless you are artificially setting it up. I find that most shooters tend to automatically center the dot in the window as they complete the trigger press.

[Pasanova]

Again, I don't think you should be able to induce the amount of parallax that you are getting with a quality red dot. Something may be wrong with either the optic or how it is mounted to to slide.

As far as how to deal with the issue of parallax more generally, it's the same as using an RDS on a carbine or, to an extent, reading iron sights. You still need to understand the aiming device and how it affects what you need to see to make a given shot. If the dot is buried all the way to the side of the window, trying to make a shot that is a very low probability shot (given shooter skill, mechanical accuracy, and ammo) probably isn't going to work. However, I think that this is also something that is very hard to do unless you are artificially setting it up. I find that most shooters tend to automatically center the dot in the window as they complete the trigger press.

I’ve been able to replicate the above with a Trijicon RMR 2, Trijicon SRO, and a Holosun.

[Alpha Sierra]

Several co-workers have purchased Glocks and Sig p320s with RMR and other slide mounted red dot optics. We are in the process of having pistol red dots approved as an optional item. I have been shooting iron sighted pistols for over 35 years and use them pretty well. I've tried a few of the red dot equipped pistols and found an issue that I'm hoping someone here can help me with.

Say I have a Glock 17 MOS with a Trijicon RMR2 and suppressor iron sights. The RMR2 and iron sights shoot point of aim/impact. My target is a 3x3 inch card at 15 yards. I purposely place the left edge of the front sight against the leftmost edge of the rear sight. This means the bullet will impact to the left and completely miss the card. While maintaining the above iron sight alignment/sight picture, I place the red dot on the center of the 3x3 card, I miss the target to the left every time, even though the red dot is in the center of the target.

What am I missing?

What you're missing is that the iron sights and the RDS are two completely independent sighting systems and should be used as such.

When aiming with the RDS, disregard the sights

When aiming with the sights, disregard the dot

[joshs]

I’ve been able to replicate the above with a Trijicon RMR 2, Trijicon SRO, and a Holosun.

I attempted to replicate this with both a PA Microdot on a Ruger MKIV and an Aimpoint Acro on a G19G5. I used 2in circle targets at 15 yards. The combo of the ammo I was using and my general rustiness these days created a little more noise in the test, but I don't see any noticeable shift except that shooting with the dot buried on the right side of the window felt very uncomfortable and showed in the results.



ETA: The three hits on the left of the bottom target were not part of the test.

[Pasanova]

Thanks for running that test JoshS. What I'm experiencing is parallax due to a poor grip on the pistol. With iron sights, even with a poor grip, as long as my front sight is in the rear notch I don't experience missing like I described in the first post. With the red dot, I don't have a rear reference point and will have to make sure that the dot is more centered in the glass.

With a rifle mounted red dot, you have contact with your shoulder and cheek to assist with looking through the center of the optic. It's this lack of consistency with the handgun red dot that I'm struggling with.

I understand that when using the red dot you ignore the iron sights. I was only using both in my original post was an example of what I was experiencing.

[SoCalDep]

Thanks for running that test JoshS. What I'm experiencing is parallax due to a poor grip on the pistol. With iron sights, even with a poor grip, as long as my front sight is in the rear notch I don't experience missing like I described in the first post. With the red dot, I don't have a rear reference point and will have to make sure that the dot is more centered in the glass.

With a rifle mounted red dot, you have contact with your shoulder and cheek to assist with looking through the center of the optic. It's this lack of consistency with the handgun red dot that I'm struggling with.

I understand that when using the red dot you ignore the iron sights. I was only using both in my original post was an example of what I was experiencing.

The way you describe this (it’s the internet so words on a screen only go so far) it sounds like you are trying to reference the dot with the irons. Do you miss if you ignore the irons and place the dot in the top, bottom, right, and left of the window with the dot itself still on the target?

When you say you’ve “tried” red dot guns do you mean you purchased one and put in the same amount of time and practice you do with iron sights? Did you get professional training on how to use the equipment like you did with iron sights?

I’m not trying to be confrontational, but at this point, the biggest issue with pistol optics is that we have lots of shooters who only know irons and forgot all the work to get good with them - look at dots and figure they should be just as good as irons when they “try” them. Like Yoda said - you have to unlearn what you have learned, and that means the learning process needs to be approached from a “new” perspective. The problem may very well not be the optic, but may be more because you’re not approaching it the right way. How many people have we had to re-teach because they learned to shoot in a way that isn’t compatible with our methods? This is same.