If your installing a new one, or re-staking the original one, make sure there is no debris in between the tube and the frame, so the tube goes all the way down on the frame.
Make sure you use the internal support pin from Brownells, or use tight fitting drill bits, to support the tube, to prevent distorting the plunger holes.
If you have the original removed, or pulled away far enough from the frame, it's a good idea to deepen the recess that you stake the rivets into.
This allows a wider area for the rivet to expand in.
Many factory guns don't have hardly any recess for rivet expansion, and this is a main cause of loosening in my experience; not being well staked in the first place.
An 1/8" round Carbide bur works well to deepen recess areas. Use at real slow speed in a drill motor. A Dremel is a bit to fast even at lowest speed for my liking.
I'd use some Permanent Type Locktight when you stake it. Don't forget to protect the finish.
Good luck- Joe