I am using Aimpoint. I also am using Surefire scout lights due to their impact buffers. Shotguns are absolutely brutal. Ive torture tested most things with full power buck, and have had to alter how I would normally do things on an AR, for these gauges. I use IWC light mounts. Torque to 30 in lb, and use Loctite 243. I torque the mount to scout body to 20 in lb, using loctite 243. The scalarworks to T2 interface gets NO locker except what nylok is on the SW screws, on account of the T2 using helicoil inserts. The SW to receiver juncture, I torque to 15 in lb, and avain use loctite 243. I de-grease all male and female threads with acetone, and apply loctite to the female threads instead of the male. This is because the first 2 to 4 threads on the tip of the bolt are what do the lion's share of the work. When you loctite the male threads, these are typically wiped near clean of threadlocker dhring the threading process by the time the bolt is seated and tight. I wipe off the excess and allow full 24 hour cure time. This keeps my stuff from rattling off when I run it hard with full power stuff for hundreds of rounds per day.
Ive seen enough stuff fall off guns in 5.56 carbine courses. I KNOW there are plenty of gauges out there with stuff just hanging on by a prayer, lol!