So, having 7.5 joules is nice. It may dissuade the individual who just entered your home from staying and possibly harming you and your family. However, upwards of 6x that power will most definitely put an exclamation point on your declaration for them to leave your property. Did the hollow door test. 7.5 j broke through first layer of thin wood and lodged into the void between. This shot clean through both sides up to 12 times and ripped through the tarp behind it the first 3. Going to fill a cat litter box with sand and test it on that next. Should be quite impressive results.