If you haven't already done so, take the trigger assembly out by drifting the pins out of the receiver. Take the magazine inner tube out. Slide the barrel back into the receiver and install the takedown screw. Reinstall the trigger. This is a little tricky as I recall, but not hard after you do it a time or two. When it gets into the correct position it will just fall in place. Make sure the hammer is cocked though when you put it back in and the safety is "ON". Finally put the magazine tube back in and you are done.
You can not put the barrel back in without taking the trigger assembly out because the back of the breech bolt will hang up on the shell carrier.
Have patience, you'll get it. The folks at the factory did it and they are not any smarter than you.
EJ
