Core shot a-spec - SightMark SM26017 Core Shot A-Spec FMS 1x 28x18 mm Obj 5 MOA Illuminated Red Dot

This was my first experience with a reflex sight, so I don’t have an expert opinion, but I knew I was buying a “cheap” sight to start with. I put this on my AR - easy install. I would say you certainly need to apply locktite to the set screws before shooting (seems like a no-brainer). This is an absolute co-witness set up (with A2 iron front sight). I’ve been told by people that sightmark is an “airsoft” tier brand, but it sighted in nicely (albeit the windage adjustment appears to be opposite of the markings) and has held zero over the initial 300 rounds I’ve put through it. I will be upgrading in the future, but it works as expected.