What holds the tube in place ? The outer tube is moving when you pull the inside sleeve out to load it. TIA

They are usually pinned. Just use a drip of epoxy or super glue to keep it from moving. I usually do it where the tube goes into the action, but you can do it at the front too, just make sure you don't get glue into the cutout for the nib that hold the inner tube in.

Thanks
Used some epoxy, rifle was a pleasure to shoot. Will try to do something with the trigger this winter.