humm ok, I will ask a question of what I'm talking about

Thank you for the replies so far.
So I recently bought a lakefield mossberg 500a here on the EE, it was made in 1980. It looks to be in good condition, it even came with a new hogue buttstock and foreend along with the original wood parts. Recently, I was showing it to a friend of mine and he racked the slide to feel the action. When came forward, the ring on the front of the grip that hold it on came off and the handle was no longer attached to the bars at the back of the mag tube.(near the receiver).
No problem I thought. I looked at it and saw it was threaded so I put it back together and screwed the ring back on. Problem over or so I thought. I went out to shoot it the other day and after firing the first round, the ring popped off the threads and the handle was loose again. I showed it to another buddy of mine, and he said he was able to push the ring on over the first half of the threads and that the threading was pretty much ####ed.
I tried this forcing the ring over the thread and it does easily push on for the first half. Should I replace the ring, the mag tube, or both and just be done with it?
Here are some pics:
the magazine:
the threaded ring:
I sent mossberg an email asking them what I should do as well.
does buying from them cost a lot regarding shipping and importing?
Don't use E-Bay for anything. They are extremely anti-firearm ownership and provide the assorted anti-firearm ownership gangs with money.
It's highly unlikely a slide will wear out but go here. Add the W's.
.mossberg.com/canada-customer-service
Ty for the tip there! I also thought ebay was not the place to buy form regarding firearms.
I bought one from High Caliber in Mission BC.... here is the link
http://www.hical.ca/promag-mossberg-forend-tube/
Ty for the canadian link! funny how this price is the price of brownells vs here is flipped! 47.99 vs 74.99 why is this? do canadians get hosed for everything?
I don't get it buddy, please explain.