In recent years there have been a significant number of coiled tubing (CT) failures during frac-plug drill-out operations. These failures occur most often when an axial vibration/pulsation extended reach tool (ERT) is included in the bottom hole assembly (BHA). There are significant efforts in the industry to first understand and then mitigate these failures. This paper examines the dynamic axial vibrations caused by these tools, and how these vibrations are amplified in the wellbore, possibly causing the material damage that later causes the failures. In some cases, these amplified vibrations have damaged surface equipment.