[ARCHIVED THREAD] - MBUS Apertures (Page 1 of 2)
Posted: 4/29/2009 6:17:38 AM EDT
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I got my MBUS from DSG Arms (dsgarms.com) a few days ago. This is my second order from them and their customer service has been top notch both times.
Anyway, I haven't installed the MBUS yet, but in looking it over I noticed a few things. 1) The small aperture is higher than the large when inserted into "firing" position. I'm guessing this is to keep point of impact up at longer ranges (like an M16A2 flip aperture). If this is so, am I to use the large aperture from 0 - 200 meters and tha small aperture beyond. How do you recommend sighting this in? I use the Santos Improved Battlesight Zero on A2 rear sights, and I like how that works. 2) The center of the small aperture is slightly left of the center of the large aperture. Is this normal? If so, any idea why? Other than that, I'm amazed at how solid this thing is. Whatever polymer they use at MagPul has been carefully researched. Thanks in advance for any information that you may have. |
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I asked a friend of mine who is a captain in the army this same question. He said that the small aperture is for daytime shooting and the large one is for use at night. I've heard the same explanation from military guys, i bite my tong, but think they are wrong... I always thought it was for long and short range setting but i wonder, any one know? |
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I asked a friend of mine who is a captain in the army this same question. He said that the small aperture is for daytime shooting and the large one is for use at night. I've heard the same explanation from military guys, i bite my tong, but think they are wrong... I always thought it was for long and short range setting but i wonder, any one know? I agree with you too. I always thought it was a long/short range setting. I figured my army friend is right though because he used to head up the rifle range at Fort Jackson. |
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Mine only has 1  
I got black and FDE from DSG and both only have 1 sight aperture. Does any other MBUS only have 1? Are you sure it only has one? when the small aperture is in use it looks like on complete unit. The parts actually snap together to make the small aperture. If you look closely you should be able to split the aperture and fold the front part down. |
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Mine only has 1
I got black and FDE from DSG and both only have 1 sight aperture. Does any other MBUS only have 1? Are you sure it only has one? when the small aperture is in use it looks like on complete unit. The parts actually snap together to make the small aperture. If you look closely you should be able to split the aperture and fold the front part down. You're right. I'm an idiot 
Didn't even notice. Great sights btw |
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I didn't notice the separate apertures either, didn't even think about it until this thread.
The instructions reference http://www.magpul.com/tech/mbus.html but that page doesn't exist yet. I took a picture just in case anyone else wants to see the two apertures. 
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I got my MBUS from DSG Arms (dsgarms.com) a few days ago. This is my second order from them and their customer service has been top notch both times. Anyway, I haven't installed the MBUS yet, but in looking it over I noticed a few things. 1) The small aperture is higher than the large when inserted into "firing" position. I'm guessing this is to keep point of impact up at longer ranges (like an M16A2 flip aperture). If this is so, am I to use the large aperture from 0 - 200 meters and tha small aperture beyond. How do you recommend sighting this in? I use the Santos Improved Battlesight Zero on A2 rear sights, and I like how that works. 2) The center of the small aperture is slightly left of the center of the large aperture. Is this normal? If so, any idea why? Other than that, I'm amazed at how solid this thing is. Whatever polymer they use at MagPul has been carefully researched. Thanks in advance for any information that you may have. Huh, I just noticed this on both MBUS's that I have. The small aperture is left and high. |
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Here is a thought on the offset (misaligned?!?) hole... There is an explanation that *COULD* be the reasoning behind this... without dissecting a MBUS, I would not know for sure... However... If the aperture is fixed to a shaft that is threaded, rotating it 90 degrees to change apertures could infact rotate the threaded shaft, which would change the position of the sight laterally. Perhaps this offset hole is like that to compensate for the lateral shift caused by rotating the aperture on the threaded shaft/screw. Again, just food for thought. Or, perhaps someone has their Jig indexed incorrectly, or the mould is incorrect. Just throwing out ideas. Can you check to see if rotating the aperture would rotate any threaded parts? If so, then it is most likely intentional (the offset hole) and I would leave it alone. |
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It looks fine to me. Does it look out of center when aiming through it? I can't tell if it's off centered by just looking through it (maybe others can, I'm no expert marksman ), but I'd assume that if the larger aperture is meant for longer ranges, then the slightest bit off center would translate to greater shifts of POI. You can see the shadowing around the small aperture is uneven, and that's not because I took it at an angle.
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Mine looks just like yours, and as you said, that's not shadowing in the photo ... it really is off to the left. It appears to be a significant amount. If you would like we can take a look at it for you and/or send out a replacement. Over all if you zero with the small I doubt you will see any difference in shot placment switching to the large with such a small shift. But of course that depends on how much the shift is. |
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Mine looks just like yours, and as you said, that's not shadowing in the photo ... it really is off to the left. It appears to be a significant amount. If you would like we can take a look at it for you and/or send out a replacement. Over all if you zero with the small I doubt you will see any difference in shot placment switching to the large with such a small shift. But of course that depends on how much the shift is. I do not understand this statement. The offset I saw in the pics appeared to be significant. You would certainly see a difference in windage. Edit: rack grade guns are said to be "4 minute of angle" rifles. If the rifle is already 4moa off the rack, why would I want to add another 2 MOA errror? |
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Mine looks just like yours, and as you said, that's not shadowing in the photo ... it really is off to the left. It appears to be a significant amount. If you would like we can take a look at it for you and/or send out a replacement. Over all if you zero with the small I doubt you will see any difference in shot placment switching to the large with such a small shift. But of course that depends on how much the shift is. I do not understand this statement. The offset I saw in the pics appeared to be significant. You would certainly see a difference in windage. Edit: rack grade guns are said to be "4 minute of angle" rifles. If the rifle is already 4moa off the rack, why would I want to add another 2 MOA errror? Again without seeing or measuring the amount of the offset I cannot tell you how much of a shift if any would be discernable. I am not going to judge based upon photographs. My statement comes from shooting the M16A2 exclusively with iron sights for over six years in the military. We did a lot of shooting with both apertures and when you focus on the front sight post the large rear aperture get real fuzzy harder to center exactly. When using the sight at the recommended distance of 0-2 with the large aperture, I found that minor windage changes did not really have any noticeable effect on shot placement for these short distances. Note: Switching back to the small aperture did give me enough detail for these windage changes to start showing up on my groups. This is just my personal experience and of course YMMV. Please also note we have no problem exchanging the sight and seeing exactly how off the alignment is and making any required changes to our QC process to resolve future issues. |
| Roger that, and this is exactly the kind of contructive process that seperates your company from the others - you guys obviously care enough to listen and make any changes if they are needed. My comments were intended to be constructive, I trust they were rec'd that way. And it is hard to judge from the photos. What I appreciate is your coming into the thread and showing you guys have a genuine concern for quality. I'd like to see the OP or someone who is able, to MIC the offset and report back on the difference in numbers. If it is capable of measurement, it can be analyzed and possibly corrected by your production processes, if that is determined to be warranted. |
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Quoted: These aren't my sights, just pics I took of a friend's gun. http://www.danpassaro.com/img/v6/p656849353.jpg http://www.danpassaro.com/img/v6/p632894309.jpg http://www.danpassaro.com/img/v5/p541044271.jpg I just received my MBUS's last night and they look exactly the same. I was a little bummed to find that the small aperture doesnt fit snug inside the large ap. It seems that with the beveled design of the inside on the large aperture, the small ap should rotate and be able to seemlessly fit inside it. Not sure how annoying it will actually be at the range. Plan on taking it out this weekend and checking them out. Anyone else find the fit between the small and large apertures annoying/problematic ? Are all MBUS's like this or just a certain run of them? Most images online show them either in the down position or in the up position facing the front. I cant tell if this small ap lineup is normal? |
| I just received two of the rear mbus sights. I've only taken one out of the package but that one does have the exact problem being discussed here. I haven't tried it yet, but it looks like it's off enough that you won't be able to use the same zero for both apertures. When I get a chance, I'll see if I can get a measurement to somehow quantify how much the apertures are offset. |
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Not sure if this applies to the MBUS, but on A2 flip rear peep aperture, there is a height difference between the large and small aperatures due to the intended range applications (as has been discussed here) AND there is a slight left/right center difference to make up for the slight left/right movement the aperature makes along the threaded shaft as you move it 1/4 turn from the up to down position. |
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I just received a black rear sight from AIM. I see no problem with the apertures lining up.
I feel rather lame for not even knowing that there are two apertures. I was very happy to find the large short range aperture. I have one sight on my SBR and am thinking of cutting off the long range aperture since I will never shoot past 200yds with it. |
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I just received a black rear sight from AIM. I see no problem with the apertures lining up. I feel rather lame for not even knowing that there are two apertures. I was very happy to find the large short range aperture. I have one sight on my SBR and am thinking of cutting off the long range aperture since I will never shoot past 200yds with it. Never is a long time. You looking at saving weight or what by cutting it off? 
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Not sure if this applies to the MBUS, but on A2 flip rear peep aperture, there is a height difference between the large and small aperatures due to the intended range applications (as has been discussed here) AND there is a slight left/right center difference to make up for the slight left/right movement the aperature makes along the threaded shaft as you move it 1/4 turn from the up to down position. this makes sense. Anyone know what the thread pitch is on the screw? Is it the same as on a carry handle rear sight? And with that stated pitch angle, what is the offset distance for a quarter turn? This could resolve the issue if it were accurate. |
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Not sure if this applies to the MBUS, but on A2 flip rear peep aperture, there is a height difference between the large and small aperatures due to the intended range applications (as has been discussed here) AND there is a slight left/right center difference to make up for the slight left/right movement the aperature makes along the threaded shaft as you move it 1/4 turn from the up to down position. this makes sense. Anyone know what the thread pitch is on the screw? Is it the same as on a carry handle rear sight? And with that stated pitch angle, what is the offset distance for a quarter turn? This could resolve the issue if it were accurate. No it won't. The A2 flip aperture has the offset because it is...a flip aperture. In order to get the two apertures lined up in windage for their usable positions, yes a slight offset may be used. The mbus sight does not have a flip aperture. The large aperture is always up, and the small aperture rotates down when you don't want to use it. Who cares if it's not lined up in windage when it's rotated down? When the small aperture is up in the usable position, it *should* line up exactly the same in windage as the large aperture. There's no reason for an offset. The problem is when the small aperture is in the usable (up) position, not in the down position. ETA: I took a quick look at my second mbus, and it appears that it doesn't have the problem. I need to get the two I have side by side and compare. |
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Mine only has 1
I got black and FDE from DSG and both only have 1 sight aperture. Does any other MBUS only have 1? Are you sure it only has one? when the small aperture is in use it looks like on complete unit. The parts actually snap together to make the small aperture. If you look closely you should be able to split the aperture and fold the front part down. You're right. I'm an idiot
Didn't even notice. Great sights btw Dur you educated me too. THANKS!
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Not sure if this applies to the MBUS, but on A2 flip rear peep aperture, there is a height difference between the large and small aperatures due to the intended range applications (as has been discussed here) AND there is a slight left/right center difference to make up for the slight left/right movement the aperature makes along the threaded shaft as you move it 1/4 turn from the up to down position. this makes sense. Anyone know what the thread pitch is on the screw? Is it the same as on a carry handle rear sight? And with that stated pitch angle, what is the offset distance for a quarter turn? This could resolve the issue if it were accurate. No it won't. The A2 flip aperture has the offset because it is...a flip aperture. In order to get the two apertures lined up in windage for their usable positions, yes a slight offset may be used. The mbus sight does not have a flip aperture. The large aperture is always up, and the small aperture rotates down when you don't want to use it. Who cares if it's not lined up in windage when it's rotated down? When the small aperture is up in the usable position, it *should* line up exactly the same in windage as the large aperture. There's no reason for an offset. The problem is when the small aperture is in the usable (up) position, not in the down position. ETA: I took a quick look at my second mbus, and it appears that it doesn't have the problem. I need to get the two I have side by side and compare. The MBUS small aperture should have a small "up" offset to help adjust for a longer range. |
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Not sure if this applies to the MBUS, but on A2 flip rear peep aperture, there is a height difference between the large and small aperatures due to the intended range applications (as has been discussed here) AND there is a slight left/right center difference to make up for the slight left/right movement the aperature makes along the threaded shaft as you move it 1/4 turn from the up to down position. this makes sense. Anyone know what the thread pitch is on the screw? Is it the same as on a carry handle rear sight? And with that stated pitch angle, what is the offset distance for a quarter turn? This could resolve the issue if it were accurate. No it won't. The A2 flip aperture has the offset because it is...a flip aperture. In order to get the two apertures lined up in windage for their usable positions, yes a slight offset may be used. The mbus sight does not have a flip aperture. The large aperture is always up, and the small aperture rotates down when you don't want to use it. Who cares if it's not lined up in windage when it's rotated down? When the small aperture is up in the usable position, it *should* line up exactly the same in windage as the large aperture. There's no reason for an offset. The problem is when the small aperture is in the usable (up) position, not in the down position. ETA: I took a quick look at my second mbus, and it appears that it doesn't have the problem. I need to get the two I have side by side and compare. The MBUS small aperture should have a small "up" offset to help adjust for a longer range. Yes, I understand that the mbus doesn't have the apertures on the same plane in elevation. I'm talking about the "left to right", what I'm calling windage, offset. I know Magpul will take care of any problems, but people seem to by trying to justify an offset between the two apertures in windage, which there is no reason to have and in fact is undesireable. Unless you don't like to have the same windage zero between the two apertures. |
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I just received a black rear sight from AIM. I see no problem with the apertures lining up. I feel rather lame for not even knowing that there are two apertures. I was very happy to find the large short range aperture. I have one sight on my SBR and am thinking of cutting off the long range aperture since I will never shoot past 200yds with it. I would not cut it off unless you have at least tested your groups with both. The small aperture is far more accurate (better sight alignment) than the large, even in short distances. The reason they say to move to a large aperature for short distances in the military is that they don't want your field of view to be limited. |
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Not sure if this applies to the MBUS, but on A2 flip rear peep aperture, there is a height difference between the large and small aperatures due to the intended range applications (as has been discussed here) AND there is a slight left/right center difference to make up for the slight left/right movement the aperature makes along the threaded shaft as you move it 1/4 turn from the up to down position. this makes sense. Anyone know what the thread pitch is on the screw? Is it the same as on a carry handle rear sight? And with that stated pitch angle, what is the offset distance for a quarter turn? This could resolve the issue if it were accurate. No it won't. The A2 flip aperture has the offset because it is...a flip aperture. In order to get the two apertures lined up in windage for their usable positions, yes a slight offset may be used. The mbus sight does not have a flip aperture. The large aperture is always up, and the small aperture rotates down when you don't want to use it. Who cares if it's not lined up in windage when it's rotated down? When the small aperture is up in the usable position, it *should* line up exactly the same in windage as the large aperture. There's no reason for an offset. The problem is when the small aperture is in the usable (up) position, not in the down position. ETA: I took a quick look at my second mbus, and it appears that it doesn't have the problem. I need to get the two I have side by side and compare. The MBUS small aperture should have a small "up" offset to help adjust for a longer range. Yes, I understand that the mbus doesn't have the apertures on the same plane in elevation. I'm talking about the "left to right", what I'm calling windage, offset. I know Magpul will take care of any problems, but people seem to by trying to justify an offset between the two apertures in windage, which there is no reason to have and in fact is undesireable. Unless you don't like to have the same windage zero between the two apertures. Krich, I think I'm tracking now, thanks. |
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Not sure if this applies to the MBUS, but on A2 flip rear peep aperture, there is a height difference between the large and small aperatures due to the intended range applications (as has been discussed here) AND there is a slight left/right center difference to make up for the slight left/right movement the aperature makes along the threaded shaft as you move it 1/4 turn from the up to down position. this makes sense. Anyone know what the thread pitch is on the screw? Is it the same as on a carry handle rear sight? And with that stated pitch angle, what is the offset distance for a quarter turn? This could resolve the issue if it were accurate. No it won't. The A2 flip aperture has the offset because it is...a flip aperture. In order to get the two apertures lined up in windage for their usable positions, yes a slight offset may be used. The mbus sight does not have a flip aperture. The large aperture is always up, and the small aperture rotates down when you don't want to use it. Who cares if it's not lined up in windage when it's rotated down? When the small aperture is up in the usable position, it *should* line up exactly the same in windage as the large aperture. There's no reason for an offset. The problem is when the small aperture is in the usable (up) position, not in the down position. ETA: I took a quick look at my second mbus, and it appears that it doesn't have the problem. I need to get the two I have side by side and compare. The MBUS small aperture should have a small "up" offset to help adjust for a longer range. Yes, I understand that the mbus doesn't have the apertures on the same plane in elevation. I'm talking about the "left to right", what I'm calling windage, offset. I know Magpul will take care of any problems, but people seem to by trying to justify an offset between the two apertures in windage, which there is no reason to have and in fact is undesireable. Unless you don't like to have the same windage zero between the two apertures. Yes I agree with you, the design of the MBUS aperatures do not require a a left to right offset to compensate for the screw. I just wanted to add that the up and down offset (elevation) is intentional. We will look into this issue and make an assessment. |
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MAGPUL, Can you please post an image of what a "flawless" MBUS should look like? A close up image showing the back (the part someone looks through) of the REAR MBUS would allow the rest of us to see if ours are correct and something we just need to get used to, OR, if ours are different and there is something that needs to be done. I think an image would help a lot of us. thanks. |