Hello. We're sorry your HD70 did not perform properly for you. We would have liked to have helped you figure out what was causing the tool to react like it did. ™. There are enough variables in wall construction (insulation properties, moisture issues, general inconsistencies, etc. etc.) that we would have had to do some trouble shooting with you to figure it out. We help our customers with issue like this every day, and we stand behind our products. Thank you.