Stack of two models unstable bouncing

edit

Greetings. When I stack two one-link models (each is just a hollow cylinder, like a roll of paper towels) they keep colliding and bouncing until the top one finally gets thrown off. The STL is available here. The sdf and world files are pasted below. The animated gif shows the behavior. At the end of the gif, Gazebo show the collision and inertial elements. The inertial element is a bit off-center; I don't see why that would cause this but thought I should mention it. Can you help me get a stable stack of these models?

This is in Gazebo 9. In model.sdf I changed the restitution_coefficient tag from 0 to 0.5 in a failed attempt to resolve the issue (even though 0 should be the less bouncy value).

Model sdf:

<sdf version='1.6'>
  <model name='Neleski_Cone_full'>
<link name='Neleski_Cone_full'>
  <pose>0 0 0 0 0 0</pose>
  <inertial>
        <pose>0.15 -0.15 0.14605 0 0 0</pose>
        <mass>130.96</mass>
        <inertia>
          <ixx>1.61005</ixx>
          <ixy>5.1652e-33</ixy>
          <ixz>5.85205e-33</ixz>
          <iyy>1.61005</iyy>
          <iyz>5.04266e-17</iyz>
          <izz>1.35779</izz>
        </inertia>
  </inertial>
  <collision name='Neleski_Cone_full_collision'>
    <surface>
      <bounce>
    <restitution_coefficient>0.5</restitution_coefficient>
      </bounce>
    </surface>
        <pose>0 0 0 1.5708 0 0</pose>
        <geometry>
          <mesh>
    <scale>.001 .001 .001</scale>
    <uri>model://Full_Cone/meshes/Neleski_Cone_full.STL</uri>
          </mesh>
        </geometry>
  </collision>
  <visual name='Neleski_Cone_full_visual'>
        <pose>0 0 0 1.5708 0 0</pose>
        <geometry>
          <mesh>
    <scale>.001 .001 .001</scale>
    <uri>model://Full_Cone/meshes/Neleski_Cone_full.STL</uri>
          </mesh>
        </geometry>
  </visual>
</link>
  </model>
</sdf>

World:

<sdf version='1.5'>
  <world name='default'>
<!-- A global light source -->
<include>
  <uri>model://sun</uri>
</include>
<!-- A ground plane -->
<include>
  <uri>model://ground_plane</uri>
</include>

<model name='Neleski_Cone_full_1'>
  <include>
    <static>0</static>
    <uri>model://Full_Cone</uri>
    <pose>-1 0 0.1 0 0 0</pose>
  </include>
</model>

<model name='Neleski_Cone_full_2'>
  <include>
    <static>0</static>
    <uri>model://Full_Cone</uri>
    <pose>-1 0 0.5 0 0 0</pose>
  </include>
</model>
  </world>
</sdf>