3. Use the Wrong Lube.
WD-40 has more uses than duct tape, but lubricating guns isn't one of them. Under the heat of firing, WD-40 and burned powder form an inky sludge that clogs moving gun parts. That sludge, I am here to tell you, is a bear to remove. Stick to lubricants specifically made for guns. Rem Oil, for instance, contains Teflon lubricant and keeps guns running smoothly in all conditions.