Okay, I haven't done this but have has similar problems a lot from what the topic says.

Bone rotation is local, right? It's the actor's local space?

If so, you will probably need "vec_rotateback".

// rotate bone13 towards bone14
vec_for_bone(gvTemp, my, "bone14");
vec_for_bone(gvTemp2, my, "bone13");
vec_diff(temp, gvTemp, gvTemp2);
vec_rotateback(temp, my.pan); //should rotate back to simulate local space
vec_to_ang(temp, temp);
ent_bonereset(my,"bone13");
ent_bonerotate(my,"bone13",temp);


Not tested.