Does anyone know if the A1.5 rear sight has a same plane aperture? Thanks.
Nope.
Thanks TOMTOM. I had to ask to be sure because I ran across a few product descriptions online that indicated it had a same plane aperture.
OK I have to ask: What’s a “same plane” aperture?
small aperture and large aperture are on the same line.
this will result in your zero being the same with both.
most sights are not same plane, so the small aperture will place your shots higher if you zero with the large.
Both aperture holes are on the same plane, meaning there’s no shift in point of impact when you switch between sizes.
I installed one of the XS sights same plane apertures on my DD 1.5 and it works fine.
OK thanks guys… Now how far off are they typically? Based on this I assume if wanting to zero irons for longer ranges it would be wiser to use the small aperture? That way the large aperture isn’t likely to matter much cuz at 50 yds or less it’s not going to be off enough to make a significant difference?
My impression was that they were on the same plane, and only differed in size: the smaller for accuracy, and the larger for quick alignment. But for me, the large aperture on the DD A1.5 is so gigantic, it is hard to tell what plane its on. And the small is too small. I wonder if there is a little insert one could attach to the large one to reduce it. I suppose I could drill out the small one…
all zeroing should be done with the small aperture. the large aperture marked 0-200 is for close in.
IIRC, military doctrine using the A2 windage and elevation rear sight indicates a 300 meter zero with the small aperture. most folks now use the 50/200 yard zero that gives a POI that is no more than a couple inches from POA out to about 250 yds.
Can someone get out their caliper and measure if they are on the same plane? I am curious now, too.
My set is same-plane (verified by observation, and by the fact that both are marked “0-2”).
Any chance they have two different SKUs? My same-plane rear is marked "DD-11002:.
Anyone confirm this one way or another by, you know, contacting the manufacturer? 
I have always been under the impression that they were not same-plane but the one I use has a Howe leaf in it now so I can’t check mine.
FWIW, I ordered a Troy fixed rear for some iron sight training I’ll be doing precisely because I did not believe the DD was same-plane. I started this thread precisely to help me make my decision.
You can usually tell by looking at the aperture mechanism. If one of them has an offset in the aperture tab then it would be same plane. I don’t understand why you think this is important. The two apertures are for two distinctly separate uses.
Mine definitely appears to be same-plane. The holes in the two apertures are different sizes, but the actual external diameter of the apertures are identical and appear to have been drilled in the same spot for each.
What they were designed for in an outdated model is irrelevant.
Is it that hard to understand why someone would want the same POI for both apertures?
I just got off the phone with DD tech support. I was told the DD fixed rear sight is NOT a same plane sight. He said the aperture can easily be swapped out with a same plane aperture. But DD doesn’t make one, so you’d be looking at the expense of purchasing the aftermarket aperture.
I also called Troy industries. Their fixed sight is a same plane aperture.
If I decide to go with a fixed BUIS, I guess I’ll go with the Troy.
Thanks Beat!
Could anyone give a little insight on this?
I would most likely zero for the small arperture and mainly stink with that, but could anyone explain how far off the large arperture may be when zeroed for the small?
Thanks
I never use the Large app. I flat out can’t hit shizz with it. Typically the Large app can be a foot off at 100 and a shooter’s groups will open up about a foot.
This is just a rough estimate based on my memory from class.
I remember watching the footage of new Navy Seals training… and those guys would forget and have the large app up… and thus miss the gong on the training drill.:rolleyes:
This was day time shooting too! How the hell you can look through the irons and not notice the large app is up is beyond me.
dang… well that being said I can see why someone would want a same plane arperture, but I don’t plan on using the large arperture much. Thanks Markm.