We have 7 509t's for testing at our agency. Two are being sent back this week. The first simply didn't fit on the C&H plate. We tried it on all of the plates we have from C&H and it wouldn't fit on any of them, however the other 509's fit fine. So something is out of spec., at least in our minds. The second one was discovered today by me. It was put on my gun, I got it zero'd and then it started shutting down. I would holster and when I drew the gun the unit would be off. I checked the holster to ensure it wasn't hitting anything. I changed batteries from a working model and no go, the whole thing would not turn on again.
One of the guys spoke with Holosun and they issued and RMA to get inspected.
I put a different 509 on my gun and zero'd quickly, did a qualification course and a few hundred rounds with no problems. We haven't had any other issues thus far, but it is a very limited experience in terms of rounds down range and two having issues out of 7 is interesting. Also we are testing RMR, DPP and ACRO.