When training for a class or tactical situation, dealing with an unloaded magazine or an unloaded gun in the situation is expected, all guns go empty at some point.   Most of us have the ability to plan ahead and carry extra magazines, but there may be a point where loading a magazine up will be necessary.   Maglula from Butler Creek makes a great speed loader that will help speed up the process of getting rounds from a box right into your 30rd rifle in a few seconds.   They will easily cut your loading time by 75% when used properly.

If you have a revolver, you know that bad guys may be walking around with semi-autos with 15-20 rounds and that you’ve got to make every round count if your carrying a 5 or 6 shot revolver.   You may only need 5 or 6 shots to win  a fight, but it is a fact that reloading a revolver can be done quicker than loading a magazine, so carrying a caliber specific HKS Speed loader or moon clips is always a great idea.