vdotmatrix
Member
well I can't Wait to make it out to my 100 and 200yd ranges but I ill prolly need a huge target .
Co-Witnessing Sights Issue
- Thread starter dragon011
- Start date
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This actually got me thinking too...1X prism vs true 1X red dot or no magnification (I cannot use red dot due to astigmatism). While Vortex Spitfire 1X is parallax free, the fact that you are looking through the prism glass might be the cause of image distortion. Yes, it is possible to "co-witness" the sights by just bringing the dot on top of the front sight while looking through the rear sight. The only problem was that i was shooting off paper. Or, in case when I wanted to adjust the rear sight to match the center of the scope, I had to adjust the back sight all the way to the left. Now, I zeroed my irons first, and I just had to make few clicks adjustment to the left on rear iron sight (no elevation adjustment available) prior to mounting the scope. I managed to zero in my scope after as well after. But, there was no 1/3 lower co-witness that was supposed to happen with the provided base. They were both zeroed in to 50 yds. Yet, the center of the scope was to the right by approx. 50MOA compared to my front sight when looking through the rear sight.
This is the thread I found that might be explaining the issue:
Leupold 1X14mm Prismatic - AR15.Com Archive
Will let you know more after I redo the zeroing at the range soon. Thank you all!
Rastoff
US Veteran
dragon011,
Where do you live?
Where do you live?
Rastoff
US Veteran
Drat! I was hoping you were closer. I'd love to discuss this in person. It is a little difficult to illuminate all the nuances through this forum.
ChattanoogaPhil
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Its difficult to follow what exactly you're explaining. If your irons were zeroed and then you adjusted the optic reticle to the tip of the front sight post (tip of post while looking through rear sight aperture with front sight aligned just as you do to shoot) then irons and optic are aligned. Done. It just doesn't magically move 50moa to the right. Something on that rifle is not mounted properly, loose or broken. If you're still having problems it might help to start with a pic of the rifle. For all we know you might have the optic duct taped to a plastic hanguard.
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Its difficult to follow what exactly you're explaining. If your irons were zeroed and then you adjusted the optic reticle to the tip of the front sight post (tip of post while looking through rear sight aperture with front sight aligned just as you do to shoot) then irons and optic are aligned. Done. It just doesn't magically move 50moa to the right. Something on that rifle is not mounted properly, loose or broken. If you're still having problems it might help to start with a pic of the rifle. For all we know you might have the optic duct taped to a plastic hanguard.
You understood my explanation correctly. I agree that it sounds illogical but it is exactly what happened. I did acknowledge the possibility of mounting error and as I said I will confirm it. However, in the thread I cited in my previous post I found that this was an issue with other prism scope Leupold 1X and they think it might have something to do with prism distortion of the front sight when looking through the scope. (I hope we are on the same page that prism 1X is NOT the same as classic red dot 1X or at least that is what I am discovering) Yes, both were zeroed and yet they did not co-zero. That was the issue I tried to explain all along.
Rastoff
US Veteran
When you say they don't co-witness, what do you mean? Are the iron sights close to the bottom of the optic or are they in the center?
cyphertext
US Veteran
When you shoot it this way, using the iron sights looking through the scope, does the bullet hit where you are aiming?
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This is sounding a lot like what happened when my #2 son installed an optical sight on his rifle. Simply put, some sight bases/risers have a degree of offset built into them. You have to experiment to see which way the base/riser has to be on the rifle to physically center the optic.
Put a small paint mark of piece of tape on the end of the base/riser currently at the front. Remove the scope/mount and turn it front to back and see if it's more centered. The issue might be in the riser if that's a separate part. The riser was the issue on my son's rifle.
Phil also has a point about making sure the various mounting screws are properly tightened. I made the mistake of assuming that since the factory mounted my optical sight on their base that it was properly torqued down. WRONG.
BTW, one of the great things about red dot optics is that the dot doesn't have to be in the apparent center of the optic to be on target. The bullet will (should) be where ever the dot is. If Vortex is willing to double check their scope, you might do well to take them up on it if the issue isn't the base/riser.
Put a small paint mark of piece of tape on the end of the base/riser currently at the front. Remove the scope/mount and turn it front to back and see if it's more centered. The issue might be in the riser if that's a separate part. The riser was the issue on my son's rifle.
Phil also has a point about making sure the various mounting screws are properly tightened. I made the mistake of assuming that since the factory mounted my optical sight on their base that it was properly torqued down. WRONG.
BTW, one of the great things about red dot optics is that the dot doesn't have to be in the apparent center of the optic to be on target. The bullet will (should) be where ever the dot is. If Vortex is willing to double check their scope, you might do well to take them up on it if the issue isn't the base/riser.
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I agree, it is pointless to assume other things before checking for the mounting error first. The riser is from Vortex and it should work. And yes, they are willing to look at it. They have an awesome VIP warranty. Unfortunately, I won't be able to shoot it again for couple of weeks. Also, tomorrow I am getting my torque wrench I ordered on Amazon so we will tighten that bad boy properly!
I guess the best thing is to continue this discussion when I come back from the range next time. I thank everyone here for helping me narrow down potential causes of this issue. As usual, it is always something simple, and user related. Have a great weekend everyone!cyphertext
US Veteran
This points more to a mounting issue with the optic to me. If you are looking through the optic and using the sights and POA=POI, then the effect of any amount of magnification, refraction, reflection, or a whole bunch of other optic related words is negligible.
Wish I could see this first hand... Could you post a pic looking through the sights and optic?
Dragon11- I just shot and sighted in my M&P Sport for the first time yesterday and have the same problem but to a smaller degree. I sighted in my irons with the red dot turned off, turned the red dot on afterward and it was about 2-3" to the right. I immediately brought it to align with the irons while looking through the rear optics thinking, "Duh..." and it shot left. Consistently, obviously. So I sighted in the red dot as I normally would with no irons. I have about 4-5" grouping at 100 yards with no magnification using the red dot, which I don't consider too terrible since it's my first time shooting an AR at all. BUT- it does not align with my irons, even though they are both on.
So this isn't to help as much as to 1- co-witness to your problem (see what I did there?) and 2- follow the thread and see what comes of it.
So this isn't to help as much as to 1- co-witness to your problem (see what I did there?) and 2- follow the thread and see what comes of it.
cyphertext
US Veteran
You should sight your irons in first, without the red dot even on the rifle. Then mount your red dot, and sight it.... fold the sights down, or ignore the sights if fixed. After the RDS is sighted, the dot may or may not rest centered on the front post when looking through the sights. On my rifle, the dot sits off to the right edge of my front sight post. Does not matter though, as these are independent sighting systems.
Ah ok- well that's essentially what I did. I mean, I had the red dot turned off when I sighted in the irons but the net effect is the same: my red dot is on the right edge of my irons. Or am I way off thinking that sighting it in with the red dot in place is the same if its turned off?
I kind of came to the same conclusion (that it didn't matter as they are independent) but I can be lazy and wondered if I just wasn't doing my homework in order to figure out what was up. Thanks.
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cyphertext
US Veteran
You should be fine. As long as you hit where you aim with the red dot and the iron sights it is good. I would worry if the dot wasn't anywhere near the front sight post, but if they are close but the dot is not exactly center of the post, no worries.
ChattanoogaPhil
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Hey guys, keep in mind the OP is talking about about shooting ---> 50moa to the left.
First of all.... When zeroing at the same distance, looking though the irons, the optic reticle MUST sit on top of the front sight post in order to aim at the same place on the target at the same distance when looking through the irons. If it didn't, you would be aiming the rifle at two different places on the target.
Now, if you change cheek weld and look over the rear sight aperture, or to the left or right when using the optic, parallax can come into play although Vortex claims zero parallax. There could be 1 or 2moa maybe, but in no case can it be 50moa.
If the optic and sights are for some reason significantly off the same line of sight (crooked) the sighting systems will drift apart as distance from zero changes. It would be like mounting a laser on the left side of a quad rail. Both irons and laser might be zeroed at 50 yards, but at 100 yards the laser beam will shine about 2-3in to the right on the target. In no case can it be 50moa.
If the OP is correct in his description, it is a mounting or equipment issue with the rifle, sights or optic. It isn't a sighting in issue.
First of all.... When zeroing at the same distance, looking though the irons, the optic reticle MUST sit on top of the front sight post in order to aim at the same place on the target at the same distance when looking through the irons. If it didn't, you would be aiming the rifle at two different places on the target.
Now, if you change cheek weld and look over the rear sight aperture, or to the left or right when using the optic, parallax can come into play although Vortex claims zero parallax. There could be 1 or 2moa maybe, but in no case can it be 50moa.
If the optic and sights are for some reason significantly off the same line of sight (crooked) the sighting systems will drift apart as distance from zero changes. It would be like mounting a laser on the left side of a quad rail. Both irons and laser might be zeroed at 50 yards, but at 100 yards the laser beam will shine about 2-3in to the right on the target. In no case can it be 50moa.
If the OP is correct in his description, it is a mounting or equipment issue with the rifle, sights or optic. It isn't a sighting in issue.
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cyphertext
US Veteran
First of all.... When zeroing at the same distance, looking though the irons, the optic reticle MUST sit on top of the front sight post in order to aim at the same place on the target at the same distance when looking through the irons. If it didn't, you would be aiming the rifle at two different places on the target.
[/QUOTE]
Let me know the next time you are in Dallas... We can go to the range and you can shoot my rifle and see. My red dot does not sit perfectly centered on the front sight post... it sits off to the right edge of the post.
Shoot with irons and you will hit. Shoot with dot, and you will hit.
[/QUOTE]
Let me know the next time you are in Dallas... We can go to the range and you can shoot my rifle and see. My red dot does not sit perfectly centered on the front sight post... it sits off to the right edge of the post.
Shoot with irons and you will hit. Shoot with dot, and you will hit.
