New AR

[vvet762]

I finally got to fire my new AR15 last Saturday. About 125 rounds at Hillside Shooting range. I have a question for all. The rear sight is a MBUS that has a flip up part that makes the aiming hole either smaller or larger. What is the difference? I used the smaller hole to zero at 50 yards. Now, I think I should have use the larger hole. Which is the one to use for near targets and at what distance should I change to the other size hole?

 

[Lunati]

Smaller hole is used for longer distances. Larger has a bigger FOV which makes it easier in close quarters.

 

[tetsujin79]

 

[hammer24]

If I use my aperture sight, then I use the smaller aperture. I have a magpul rear BUS, and that larger aperture is really too big for most of my applications.

 

[Vlad the Impaler]

I sight with the 300m small aperture.

Edit....
Some good reading and explanations of all you'll likely question with sighting here: http://www.m4carbine.net/showthread.php?t=65679
Post #3 has exactly what your looking for, and the 25/200m vs 50/300m M855 trajectory chart to show the result.