You need to be sure of the caliber you require. For instance, if you want a handgun for your protection then you need to buy one of the largest calibers that you can handle in terms of accuracy and safety. The point that you need to focus on here is that you should buy the ‘LARGEST CALIBER THAT YOU CAN ACCURATELY AND SAFELY HANDLE,’ and not the largest caliber hand gun. This is a very important point which most people tend to overlook, although it has a great impact on safety and on accuracy.
According to the recommendation of the NRL you should buy a minimum of .38 spcl caliber in a revolver when you are aiming to acquire a handgun for personal protection, while a 9mm is more suited for a semi-automatic. You should look for accuracy more than the size of the handgun. Also, keep in mind that you purchase a handgun whose ammunition you can afford and find easily in the market. Otherwise it will not be of much use to you.