AR optics

[pk_]

Bushnell Optics, Drop Zone Reticle Riflescope with Target Turrets, Matte Black, 1-4x/24mm https://www.amazon.com/dp/B00ABP5UXG/ref=cm_sw_r_cp_api_i_ziCLEbZDEHJBJ
Looks like a decent option.

maybe also check the Nikon P-Tactical scope.

 

[Tyeguy]

I run a Aimpoint. I also used this optic in the military. They are pretty much bulletproof, but are pricy. For close quarters shooting, you will want a reflex sight, or in other words, a red dot. These sights are designed to simply aim and shoot. This is commonly referred to as point shoulder shooting. ACOG is also very good, but more for longer range shots.

 

[NHRedleg]

On my AR carbine I run a Primary Arms red dot; an Aimpoint CompM4 clone they used to sell that is exactly like my issued optic in the Military. It is good quality for the price, holds zero without issue, has been rugged, and I wouldn't hesitate to buy one of their other red dots. I also run a 3x magnifier with that red dot when I want to reach out further. I can also run the irons should my red dot fail thru it or easily remove. I feel for close work, 100yd and in, nothing beats a red dot for accuracy and speed of target acquisition.