Troy Industries BUIS Windage Sighting Question

[KM1]

I was sighting in my Optics, BUIS, and Laser sights on my new AR (yet to be fired...and properly range zeroed) to be used with my LaserHIT targeting system. The distance I was using was about the full length of my house, wall to wall, which is 50ft long (taking into account table, chair etc.). Just wanted to see how this system might work with my AR vs my general use of the system with my handguns.

I know at 25 yds, an adjusted 100yd zero would be about 1.5" POI lower than POA....and since I am a solid 25ft less than that, it would be approximately 1.75" to maybe 2+" lower than that. However, windage shouldn't really change (I don't think).

So I find, when setting up my Troy Industries Round Rear Folding Sight, to zero it for use I have to move it FAR to the right...I am shooting left handed, sighting left eye. Is this normal or typical (images below)? I mean...I'm not sure how much more right I could even move it....there is not much room left as you can see.

I should note that I sighted in my Eotech EXPS2, as well as my laser, and the Eotech 1moa dot (dimmed very low so you can just see it), sits centered RIGHT ON TOP of the front M4 Iron sight when co-witnessing it with the Rear, small aperture. AND the laser lines up as well with all, exactly the distance below expected as it is mounted below the barrel.

I just found this strange, that the rear sight would need to be moved so far to one side to zero......and I really wouldn't know if this is common as this is my first AR, first rifle.

Now I know the typical, "always on," laser cartridge's are notoriously inaccurate as they tend to move around slightly in the chamber, never showing the same POI....however, the training laser cartridges are much better as they have "O" rings at the front and back of the cartridge to keep them solidly centered in the bore. I have an image of the one I am using below as well. I also tested it, before zeroing, to see if POI changed every time I rechambered to set the rifle up for another shot and POI's were pretty constant.

Have others found this as well...that windage adjustments tend to be farther off to one side more than the other when zeroing? Does it even matter if your able to actually zero out the rifle with POI & POA being the same at the zero one selects???

Oh....and I understand that I will have to ACTUALLY zero the rifle at the range with live ammo as that is the only true way to zero a rifle. Just wanted to see how the rifle worked with the LaserHIT training equipment I have been using for indoor, dry fire, pistol work.

 

[Downtown]

I can't say if this is your issue, but your rear sight is very similar to one I was struggling with recently. The issue turned out to be a slightly canted front sight.

 

[KM1]

I can't say if this is your issue, but your rear sight is very similar to one I was struggling with recently. The issue turned out to be a slightly canted front sight.

I put these on. They are backup, flip up sights from troy industries. There not cheap. When I visually inspect the front sight it looks perfectly vertical. How would one check this for exactness?

I find it interesting that both my EOTECH and laser sights line up with the iron sights. If it was canted....how is that possible????

 

[Downtown]

No, you're right. I was just struck by the similarity of that rear sight. I had one cranked all the way over and was stumped until I noticed the slight lean on the front sight. No, your issue is different.

 

[TMR137]

I would check to see if your handguard is slightly off center. A small degree of cant would cause your rear sight to have to be moved quit a bit. the EoTech and irons lining up with the laser is correct even if the front sight is canted. Zeroed is zeroed. The rear sight being so far off of mechanical zero, just means that your front sight post is off. What hand guard are you using? A picture of the entire set up would help us help you.

 

[KM1]

I would check to see if your handguard is slightly off center. A small degree of cant would cause your rear sight to have to be moved quit a bit. the EoTech and irons lining up with the laser is correct even if the front sight is canted. Zeroed is zeroed. The rear sight being so far off of mechanical zero, just means that your front sight post is off. What hand guard are you using? A picture of the entire set up would help us help you.

Ok...I don't know if it is sitting perfectly square on the sandbags but here are several images.

And I kid you not that Eotech 1moa dot co-witnesses perfectly with the BUIS right now, with that rear sight windage way to the right. That dot is resting centered right on top of that front iron post...like I set it on top of it. And when I pull the trigger the laser POI is exactly where it should be at the distance I am shooting. Plus, laser under the barrel same thing, perfectly even (windage), with that front post and the 1moa dot of the Eotech. Just heights is different because of mounting under barrel.

Maybe it's just the way my cheek hold and eye line up????? Oh....and this is a PWS MK 116 Mod2 right from them....handguard and all. I only added the Optics and sights.

 

[TMR137]

Being a factory rifle from PWS I would imagine the hg is straight. So I would lean more towards your laser is not shooting true to the bore and when you fire live rounds through it you will be adjusting both your EoTech and irons. I would expect the irons and EoTech to line up if you adjusted them to the same point (the laser). Them lining up right now just means you adjusted them to the same point of aim. Those training aids are really just that, aids. I have seen them be off by 2-3 inches at close range which would account for your windage adjustment.
Fire some live ammo through that thing and I bet your windage will come back closer to center.

 

[KM1]

Being a factory rifle from PWS I would imagine the hg is straight. So I would lean more towards your laser is not shooting true to the bore and when you fire live rounds through it you will be adjusting both your EoTech and irons. I would expect the irons and EoTech to line up if you adjusted them to the same point (the laser). Them lining up right now just means you adjusted them to the same point of aim. Those training aids are really just that, aids. I have seen them be off by 2-3 inches at close range which would account for your windage adjustment.
Fire some live ammo through that thing and I bet your windage will come back closer to center.

I figured I'd have to do that anyway. Simply can't count on anything but live fire for realistic zero.

However, as pictured in my op, those "O" rings are supposed to keep that laser cartridge centered. Is it your experience that they actually never work as expected?

Thanks for your help. Hopefully I won't be more than an inch or so off when I actually put rounds through the rifle to get it's TRUE zero.

 

[smoothy8500]

Almost everyone I know that used a laser device said it was way off when they actually took it to the range....

 

[KM1]

Almost everyone I know that used a laser device said it was way off when they actually took it to the range....

That figures.....looks like the old adage "there aren't ever any short cuts" holds very true here!!!

What I was trying to do, anyway, was make it useable with my LaserHIT training device I have so I could get used to all the functions (first rifle) safely, and get a little dry fire practice with the rifle. The LaserHIT system is the one that registers your shots right on your TV via one'e phone camera. To do that I needed some kind of zero to make it worthwhile. I was HOPING that I would be CLOSE once I FINALLY take it to the range to actually zero in all the optics on it. Looks like none of this is going to work out as I had hoped....LOL!!!

Thanks!!!

 

[smoothy8500]

I wonder if you were to just "boresight" the irons at 25' it might be close enough for your LaserHIT since it's good enough to be on paper at 25 yards?

 

[KM1]

I wonder if you were to just "boresight" the irons at 25' it might be close enough for your LaserHIT since it's good enough to be on paper at 25 yards?

I re-tested it today....taking out the cartridge, turning it, and replacing it 3 different times to see if MAYBE I could get it to sit centered. I actually took a piece of thin paper, held it over the end of the barrel (pressed up hard enough that it created a slight dimple and outline of the opening of the barrel, then marked the exact center of the whole that was created. I had my wife pull the trigger activating the hammer and laser to see where it hit the paper at the end of the barrel. By the 3rd time....I had it sitting as centered as possible (it was NOT exact...but very, very close...almost imperceptible).

Then I ran my LaserHIT system using the laser cartridge in the AR at that 50ft distance. The settings I had on ALL optics where identical to what I had set a couple days earlier. Basically, even thought the Iron, rear sight was way right, they all were on the money....zeroed to that adjusted distance with that 25yd adjusted target. NOTHING had changed even rotating that cartridge to different positions. It would not surprise me that even the impact of the firing pin on the cartridge moves it ever so slightly....and in doing so throws it off as well. It would not take much at all to show a 2" POI to POA difference at 50'.

I am going to bet that when I take the rifle to the range, like TMR127 said, I will be adjusting ALL of my Optics moving the POI from the right back left as the laser cartridge originally showed all hits with all optics to the left and a little low, thus, having to move the POI right and up a little to zero with that cartridge. Basically....with live ammo...I believe I will be right and high....the opposite of what the laser cartridge originally showed (left and low). We'll see....but probably won't be able to get out for months to test all this out. Oh well!!!

 

[GH41]

Have you tried to bore sight it the old fashion way?

 

[KM1]

Have you tried to bore sight it the old fashion way?

Not yet. How well does that work? When one does it that way do you typically find it right on the money when testing it out with live rounds at the range?