What CH said about the barrel bushing placement is oh so true! I have fiddled with them a great deal and some seem to want to defy what I know is the proper place for them in the stock! It is not something I want to mess with after a long day in the shop as the last thing at night before I shut the door and call it a night. Fixing one like you have and getting it in the right spot is time consuming and sometimes takes a great deal of patience. The bushing can be squared away with some kind of file to square the edges, the area it moves in has to be very clean and lightly lubed a bit too. If it is placed just right the handguard sits in such a way that you are sure of it. The metal nose trim parts usually fit easily too. If not something is not quite right so keep fiddling with it.
Like I said Patience! Bill
PS Please remind me this month as I get 7 or 8 28/30's ready about what I wrote about?
zeebill live from the hills of West Virginia!