The bead on my berretta pintail 12 guage keeps coming off the threads are not stripped, can you guys tell me what is wrong?

[Louie]

The bead on my berretta pintail 12 guage keeps coming off the threads are not stripped, can you guys tell me what is wrong?

[Johnnie]

Could be the barrel's vibration is working the bead loose. Try some threadlocker, like Loc-tite, on the threads. Be sure to get the kind that lets you remove the threaded item at a latter date, because they have a permanent type of threadlocker.

Or maybe the shank is too long on the bead or the hole is shallow preventing the bead tightening up properly. As a last resort you could shorten the shank a little at a time until it snugs up or drill and tap the hole deeper. I would avoid these two steps unless you are good at gunsmithing.
Lastly you could tell Berreta the bead keeps coming loose and ask for a new bead for your Pintail. I bet they would send you one for free.