NOTE: because of a recent law change the following information will be obsolete as of September 2011. Starting 8/28/2011 you will be able to use a NFA trust to purchase NFA firearms in Missouri without the need of a C & R, FFL, or use of a Corporation or LLC.
A trust may not obtain a C&R license. In some state like Missouri, to purchase Title II firearms you must have a FFL. Missouri considers a C&R a FFL for this purpose. A trust may not obtain a C&R or other FFL.
If you want to use a NFA Trust in Missouri, it must be done in conjunction with a Corporation or LLC. The Trust can be the member and the Manager of the LLC or Corporation which adds the ability to deal with incapacity, death, and easily changing the authorized users.