Rear apperature confusion.

[black22rifle]

I just read one of molons posts about the 0-2 aperture on rear sights and it has me a bit confused, Specifically post #3 in this thread www.m4carbine.net/showthread.php?t=65679. If the small aperture is used to zero a rifle and for normal firing positions what is the point of having a larger "0-2" aperture whose POI is low in low light conditions and movement target engagements? By zeroing the small one at 300 it automatically zeros the larger one at 200 and according to the chart shown it gives you a really flat trajectory from 0-200, is it just for ease of use? I have read elsewhere that "0-2" stands for 0-200 yards and the large aperture is for ranges past that. Is there any truth to that? Are all dual aperture BUIS such as Troy and MBUS set up that way? How will this affect a 50/200 zero and should one use the same method of zeroing, e.g. use small aperture to zero at 50yards?

[levik97]

The way I use it (and what I understood him saying) the large aperture is used for close range engagements and when shooting on the move. It's much easier to acquire the target and fire quickly when using the large aperture but accuracy is decreased. For close range, it's more than accurate enough effectively hit your target. The small aperture works great when target shooting and at longer ranges (especially when prone), however, it takes slightly longer to line it up. That's the way I see it anyway. There's a lot of people here who know better than me and I have never claimed to be smart but I hope I helped.

Levi

[thopkins22]

I have no idea if that was the intention of the sight when it was designed or not...Molon is usually on point so it probably was. But lots of things were intended to be used differently from what the community has collectively decided to do.

If you think you're going to be hitting very accurately at 200 with the large aperture then I'd wager you have another thing coming completely. Can somebody with perfectly consistent cheek weld and other fundamentals do it? Sure. Will most folks? Even most good shooters? Not likely....

Zero the small aperture at 100. Use the small aperture in bad light or inside of 25 yards. Don't think about it too much. If the light is bad enough or you're close enough to need the big aperture, it won't matter how much it's off. Don't get too caught up in what the ballistic charts say, you won't know where you're hitting at various distances until you walk the ground and check the targets.

Paul Howe, Jack Leuba, Jim Smith, and countless others with experience shooting bad people in the face push for the 100 yard zero...and pretty much everyone else of merit pushes for the 200 yard zero using 50 yards to get you close enough to fine tune it at distance.

Literally the last thing I would want is two separate ****ing zeros on my rifle, especially if the most useful one was on what is generally the least useful aperture(at least past 20/25 yards.) And the 300 yard zero is far too wacky at various distances for my tastes. I don't know what it's like to be shot at, but I know I would hate to use that zero in a match.

ETA: Curse word *'s on M4C. I missed that one. ;)

[black22rifle]

I am really only worried about my zero. I had no idea some rear sights had two different zeros and i agree that is not something i would want either.

[thopkins22]

Zero it at 100 yards. Use the big aperture at night and at close range. The variance will never(NEVER) matter.

Alternatively, go buy a "same plane" aperture for your rear sight, or a new rear sight with a same plane aperture already installed. This will also add the benefit of taking any horizontal shift out of play too. Chances are that the your Troy rear sight already has this in which case it's a total non issue. I think the MBUS is supposed to be same plane too...just different diameters but I'm not sure.

What I meant by not wanting two zeros is I would never want a 300 yard zero...and I would never want to have to remember another zero for the large aperture...which you would if your most accurate aperture was rendered useless with the 300. If you zero the small aperture at 100 or 200, and only use the big aperture for low light and close range...you'll never be able to tell whether it was a hair off or not and I would shoot it as though it was exactly the same.

[black22rifle]

I actually have the MBUS, Magpul;s website states "Protective wings shield the dual, same plane flip apertures"

[thopkins22]

I actually have the MBUS, Magpul;s website states "Protective wings shield the dual, same plane flip apertures"

Then you don't suffer from this affliction and have a consistent zero across both apertures. :)

[sinlessorrow]

If you have ever used one you will know there is a huge difference between the large and small.

The large is quite nice for close quarters and dark areas where the small one would be a challenge to use, and at that distance the large aperture will be on target even if the post is not perfectly centered.

[MistWolf]

I used to be a die hard advocate of smaller apertures for better precision.

Until my eyes got a little older. Truth is, a larger aperture is much better for fast shots and with a little practice, gives up little in practical precision

[T2C]

I have checked zero shift on a few carbines with 16" barrels and standard carry handles. I measured a 6 MOA shift in point of impact between the small and large apertures.

With the small peep zeroed at 300 yards, using the large peep caused my shot group to hit 1-1/2" low at 100 yards depending on ammunition selection.

With the small peep zeroed at 50/200 yards, the large peep caused my shot group to hit 4-1/2" low at 100 yards.

I use a 200 yard zero. When using the large peep, I hold on the hair line for head shots at 25 yards and less.