[HELP] Intact Mesh hierarchy

I've been editing the M16/M4 M203 for my personal PR mod but I cannot seem to make it work properly. I know there is linking between the mesh parts like the magazine, bolt, shells and everything aside from the main mesh but I don't know how exactly they are linked. Can anybody tell me how they are linked together or better yet suggest a procedure or program where I can see all the mesh's hierarchy intact? POE2 tools can but it required the old .con files containing the codes on how the meshes were arranged which I do not have for any weapons except for those I already exported.

Help is greatly appreciated because I've been looking for days already.