It works! It works! It works!
kinda...
I had to take out the following lines:

vec_scale(temp,1000); // set a range
vec_add(temp,mouse_pos3d);
c_trace(mouse_pos3d,temp,IGNORE_MODELS|IGNORE_SPRITES);
vec_set( mouse3d_vec , target );

vec_diff( temp , me.x , mouse3d_vec );// may need to exchange me.x and mouse3d_vec
vec_to_angle( my.pan , temp );

but once I removed them it worked!
The gun always looks at my mouse!
Thank you so much for the help!
rtsgamer706