Selecting a Handgun
If you are new to shooting or have been at this a while, you need to consider a number of factors when selecting a handgun. This article will focus on the new shooter who may be buying his or her first gun.  First and foremost you need a gun that will meet your needs.  Take a trip to your friendly neighborhood gun store or head out this this weekend's gun show.  Running a quick web search should find a few. 


"So, why do you want a gun?"  The reasons vary and can include - Self Defense, Hunting, Collecting, Target Shooting, or Competition.  I am sure there are other reasons, but let's start with these.  
Self Defense - You need a  handgun which is moderately comfortable to conceal upon your person and carry all day which you can shoot reliably to stop an attacker.  The ability to practice with this gun is important so you must be comfortable shooting this gun enough to ensure if you are in a life or death situation you will be able to place your shots where they need to go.  This means at least a hundred rounds or so in a single range session.  Some tactical training classes are 1,200 rounds over the course of a weekend.
Hunting  -  While most hunting is not done with a handgun, but there is a segment of those who do use a handgun to hunt both large and small game - you need a gun which can quickly and humanely kill the animal you are shooting.   Less practice is required perhaps than for self defense, but you still need to remain proficient.
Target Shooting/Plinking -
If you are headed to the range simply to put holes in paper targets then you want something you can shoot often, with little recoil and minimal cost.  Stopping power is not a concern so a .22 often times will work well.
Competition- What type of events will you be competing on?  You need to review the rules for the event to ensure you will be in compliance with the rules. Some of these rules may include caliber, magazine capacity, barrel length. weight of the gun and modifications.
Collecting- What type of gun will you be collecting - historic, innovative, manufacturer specific, model specific, caliber specific... there are many types of gun to collect, but this article will not really delve into that much.

Revolver vs. Semi-Auto
The modern Revolver was developed by Samuel Colt in 1836 long before the semi-auto and is a simpler machine.  The first benefit is - with less moving parts there is less opportunity for the gun to fail, but failures do occur from time to time.  The revolver is usually easier to manipulate, the shooter only needs to open/close the cylinder, pull the hammer, pull the trigger - none of these are require much strength leading this to be a gun often recommended for those with less hand strength (often older folks, women and those with limited dexterity).  Revolvers had been and continue to be offered in a variety of calibers, but the majority of revolvers are produced in .22LR (Long Rifle) .38 Special or .357 Magnum. Other less popular calibers include but are not limited to.44 Magnum, .45 Colt, and .500 S&W Magnum. Other calibers are available, but finding ammunition for them may be problematic. A revolver usually has a capacity of 5 or 6 rounds.  With no manual safety, a revolver is arguably less safe, but as long as you follow the fundamental gun safety rules this should not be large a factor in this decision.  

The modern Semi-Auto was developed by John Browning in 1896 and it a more complex machine and more opportunity for a failure to occur.  That being said, modern manufacturing processes and metallurgy have created pistols which are incredibly well built, and failures are few and far between.  As with the revolver the shooter must be able to manipulate every feature of the firearm with ease - this includes racking the slide, retracting the hammer and locking the slide back.  The spring used is different in every firearm - some are easy to retract and others are quite difficult.  Semi-Automatics are offered in a slightly wider range of calibers including .22LR .380ACP, 9mm, .40, .45ACP, and .357 Sig to name a few.   Semi-Autos typically have a larger capacity 10-16 rounds is not uncommon.  Many Semi-Autos do not have a manual safety, but many do. 

The smaller and lighter the gun the easier and more comfortable it is to conceal on your person, but the smaller and lighter the gun the more you, the shooter will feel the recoil.  Many people pick up a 2" barrel Scandium notice that it weighs less than a pound or about 12 ounces, and think it would be easy to shoot, this is simply not the case.  Because of how light the gun is; there is little mass to absorb the recoil - so the shooter absorbs it all.  A gun similarly sized made of steel might weigh about 34 ounces - which is more than twice the mass so less felt recoil.  Of course a 4" barrel .357 might weigh 39 ounces, so the conceal ability and comfort would be decreased, but the ease of shooting would be increased.  When you are looking at guns - hold it out at arms length for a few minutes, how do your arms feel?  If the gun is too heavy you may need to look at a smaller sized gun perhaps.

Caliber selection is very important you need to strike a balance between what you can shoot comfortably hand having enough power to do the job.  A bigger bullet, means more powder, means more recoil.  A .22 is likely easiest to shoot, but if chosen for self defense, it would likely not be big enough.  In self defense your goal is to stop the threat, not to KILL, but sometimes killing is necessary to stop the threat.  A .22 is big enough to kill an attacker just as dead as a .357 Magnum or .45ACP, BUT it is not as easy to do so.  If you shoot ten rounds of .22 into your attacker it may be enough to kill them, but not immediately if perhaps they are on drugs - so they may kill you back before succumbing to his/her injuries.  A laeger caliber will kill more effectively.  If you can shoot a larger caliber you should, if a .45ACP or .357 Magnum is too big (either the physical size of the gun or felt recoil) for you then look at .38 Special, or 9mm.  If you don't know which is best for you try a few guns either rented at a range or borrowed from a friend (or by taking the Sampler
Course).  If choosing for self defense, you should select the largest caliber that you can shoot, carry and train comfortably.