I've had them loosen, but I do believe it's almost always a host threading or shoulder issue. On a host with a nice reasonably wide shoulder to torque against, and the threading done right with an undercut so the can is fully against the shoulder, a quarter turn back and then snap tight, keeps them snug.Maybe I’m the odd one out here, but I have literally never had my direct threaded cans come loose over a course of fire, or while hunting. No Teflon tape, no goop, just a little wrist snap when it gets snugged up. Maybe my muzzle threads are just dirty enough to act as some security…
In the spirit of this thread, here are three rifles with Xeno mounts at the range today, two of which are hunting rifles (Sig Cross and 13" 6mm ARC AR), and two of which have Nomads mounted (albeit an old school TI and a steel nomad).

This was the Proof/Origin .223 with old steel Nomad on the 1,000yd steel no problems with repeatability with that rig, and it gets shot often because it's really fun.
