A couple of times in our monthly newsletter I have written about the need to visually and physically inspect your carry/defensive ammunition for defects before loading it into your carry handgun. Ammunition manufacturers turn out millions of rounds each day, and even those with high quality control standards ship out ammunition that is out of spec and faulty.
You need to be certain each cartridge has a primer and that the primer is not damaged. Bullets should be firmly seated in the case. Cases should be without burrs on the rim, torn mouths, and bulges. This is critical. Many handgun malfunctions are caused by faulty ammunition, and a quick inspection might save you a lot of pain later.
Today one of our students discovered a badly wrinkled round while loading his carry magazines. The case is badly mis-shaped just below the base of the bullet. This would likely cause a feedway stoppage if someone attempted to fire it. This was a Winchester Ranger factory round of .45ACP.