BAM is a 3D model archive format used by Atlus in Persona Q and Persona Q2. These files are in the CGFX model format that other Nintendo 3DS titles use, and apart from an added header they are exactly the same.
In order to view these models with any 3ds model tools you must open them in a Hex Editor (i.e 010) and delete the data up to the section that has the "CGFX" file header.
Note: Some models may contain EPL data before the CGFX header, in which case you should delete it as well.
After deleting this section of the file, you can use the tools below to view the models.
SPICA is a 3ds model viewer created by gdkchan. This tool can view models, textures and animations inside edited .BAM files.
You can download the latest SPICA build here.
Bam Editor is a tool made by Pioziomgames. Download it here.