Yesterday, while preparing for a training class, I noticed that my Acro that was mounted via a Tango Down adapter plate to MOS Glock was loose. Removing the optic, I noticed that the screws securing the plate were slightly out.
The mount was installed about 2 years ago, and the pistol was used on and off, with not that much shooting. I would estimate 1400 rounds between installation and now.
I retorqued mount screws and reinstalled the optic.