[dba-SQLServer] varchar limits

SQL2000.

I have the following declaration in a stored procedure -

         declare @qs varchar(8000)

However, when I assign a string to the variable it seems to truncate at 
4000 characters.  My understanding is that varchar can have up to 8000 
characters.  Is there something I am missing?

Regards

David Emerson
Dalyn Software Ltd
25 Cunliffe St, Churton Park
Wellington, New Zealand
Ph/Fax (04) 478-7456
Mobile 027-280-9348