Mossberg also makes barrels for the Rem 870's you can see them at
http://www.mossberg.com/acatalog/pricebarrels.htm and scroll to the bottom of the page.
I bought one of thier 18.5" parkerized cylinder bore barrels and have been quite happy with it.
But for the longer barrels, I agree with TTed, stay with the Remington barrels with removable chokes.
Chuck
[This message has been edited by chucko (edited June 10, 1999).]