Hs510c is a great value for a solid performing reflex sight - Holosun HS510C 1x0.91-1.2in Open Reflex Red Dot Sight

I have a few Holosun red dots, and find them to be reasonable quality at a reasonable price with outstanding customer service. I once dropped an AR-15 with a Holosun 515C red dot, and dented the elevation adjustment cap badly. When I tried to remove the cap, I torqued the whole adjustment mechanism out. I sent a note to Holosun and they replaced the sight free of charge with a free return label. So, I do like the company. When I saw this sight with it's larger view window I decided to give it a try. Have been unconditionally satisfied with it's performance on an AR-9 with about 700 rounds through to date. The adjustment is simple and precise, the red dot very clear and good brightness adjustability in manual mode. Automatic brightness was a bit dim for my liking. The Quick disconnect mechanism is robust and works very well. Solar panel extends battery life which was already excellent at an expected 50,000 hours.
I have not gotten around to dropping the rifle on the rocks or concrete at the range, but there is a robust titanium hood that covers the reflex optics which looks like it could take some abuse. If I get to swimming with the sight or dropping in the mud, I will provide a follow-up, however there is a torture test on Youtube where they submerse this sight, throw it 15 ft. in the air repeatedly landing on hard ground, even shoot it broadside with a 12Ga shotgun, and after every test it goes back on their test weapon and holds zero. I would highly recommend this sight.