game engine trouble PLEAE HELP

hey, when i want to shoot my crates, my bullets either go right through it (theyre not set to ghost) or it hits and the crates freak out and burst out the walls, by the way when you walk into the crates, the physics looks fine, its only when i shoot tem that they burst through the walls, THE WALLS NORMALLY KEEP THEM IN LIKE WHEN I PUSH THE CRATES INTO THEM, how do i make them hit every time with out them freaking out, heres a video i took to be more specific: http://www.youtube.com/watch?v=BVYJM3iKB3s