Excellent enclosed optic. love chevron by itself for long guns - Primary Arms Holosun HE509-RD Enclosed Solar Powered Red Dot Reflex Sight

I have several regular 509’s, and love them all. Can’t beat the enclosed nature and no rain, mud, dust getting in sight. Very easy to clean and very sturdy. Bigger buttons are far superior to other Holo offerings. Mount system is a bit tricky, but not terrible. This one uses standard 509 footprint, but is a tad longer. Actually fits better with the rmr adapter plate for aftermarket mounts because the standard 509 is shorter than an rmr, so looks a tad awkward. This one fits completely flush with included adapter plate on any rmr mount. I use this on a piggyback for AR, and on ADM low mount for shotgun. The trick is to turn off the large circle for long gun applications. The big circle only works for pistols, as it’s always visible closer to eye. But you just use the chevron only, and it’s very nice. Reminds me of the old trijicon chevron optics.