MBUS Sighting Question

[Steve02C5]

What's the accepted manner to aim the rifle using the front post, with the horizontal thumbwheel, and the rear aperture sight? Does one center the "cross" of the front sight into the center of the aperture to attain the appropriate P.O.A.? I'm ashamed to admit I've never seen nor read of this particular style of sights.

 

[Rustpot]

Center the tip of the front in the ring of the rear. This picture is close, but the front sight will be a lot larger, you won't see the protection prong as easily. The reason the MBUS sight has that "cross" is that there is less material. That portion would normally be at the base of the front sight and not be seen.
https://www.stuckonpolitics.com/wp-content/uploads/wpsc/product_images/AR-sight-picture-2.png

 

[E6type]

 

[Steve02C5]

Center the tip of the front in the ring of the rear. This picture is close, but the front sight will be a lot larger, you won't see the protection prong as easily. The reason the MBUS sight has that "cross" is that there is less material. That portion would normally be at the base of the front sight and not be seen.
https://www.stuckonpolitics.com/wp-content/uploads/wpsc/product_images/AR-sight-picture-2.png

Thanks RP, I understand most of what you wrote; however, this part I'm unclear on:

The reason the MBUS sight has that "cross" is that there is less material. That portion would normally be at the base of the front sight and not be seen.

Why is the donut shaped horizontal piece there? If it were removed, how would it affect the ability to place the top of the front sight into the center of the rear aperture?

Thanks for the input.

 

[Rustpot]

The front sight post has 3 parts - the threads to insert it, the wide "donut" as you call it, and the post itself.

The donut is there to allow a tool to slip over the post and twist it to adjust elevation. There are 4 small notches around that ring for the tool to grab the post. Without that you'd be grabbing on the thin post and risk bending it while trying to adjust it.

On a standard AR15//M16 sight block that donut is recessed slightly into the block so all you see is the post. The MBUS has less material in this location so the post can be lowered further for guns using a rear that's lower than an AR15 standard. Also so that you don't need the specific sight tool to make adjustments since you may not have access to one when you need to make adjustments.

Here's a pic of a sight where you can see how the post sits in the block
http://www.pkfirearms.com/product_images/0000/5605/DD_Front_Sight_2.jpg

And here's a rough picture of my MBUS sights to see the post sitting in the rear. I know the focus is bad, but there's the sight.

 

[Steve02C5]

Thanks RP, I get it now and do appreciate all your time and effort in responding.

 

[fastsw]

Are the mbus's reticle the same height as the stock sights?
For example, can I use an mbus rear with the stock front?
Also, who makes a descent inexpensive metal mbus set?

 

[Rustpot]

Are the mbus's reticle the same height as the stock sights?
For example, can I use an mbus rear with the stock front?
Also, who makes a descent inexpensive metal mbus set?

The rear aperture is the same height, standard AR15. It may not zero the same since the rear A1/A2 sight has elevation adjustments and the MBUS does all of the elevation with the front sight.

MBUS stands for Magpul Back Up Sights, so no one makes the MBUS but Magpul, and they only make them in polymer. If you need metal you can buy a Troy clone BUIS (back up iron sight) from a site like rrages.com, or spend a good deal of money on flip sights designed for the .223 platform.