Barrel length will affect many aspects of a gun. The right barrel length for any given purpose will depend upon a variety of factors. This article discusses barrel length considerations for firearms.
Purpose of the gun and barrel length
Different guns are often intended for different purposes by their manufacturers, and even within a single model of gun there are often sub-models intended (or at least suited) for different purposes. For example, a small concealable handgun may be great for self defense outside the home, while a long barreled shotgun may be ideal for trap shooting. Those two guns are really not interchangable, as virtually no one can lug a 40″ shotgun around all day for self defense, and small handguns are not suitable for competition trap shooting events. Obviously, the barrel length of the gun matters greatly depending upon the gun’s purpose.
Other times, a gun will be more or less ideal for a purpose, even if it still somewhat suitable. As an example, I carry a Springfield XD as my main concealed carry weapon. I could carry my Smith & Wesson Model 610 revolver instead, as it would fit into a holster that I could conceal. However, the longer barrel and larger overall size/weight of the Model 610 make it a less ideal carry weapon for me. Here, barrel length matters again.
As a general rule, hunting and target shooting guns will have longer barrels, while self defense guns will have shorter barrels. The reason that self defense guns give up barrel length is to make the gun more suitable for self defense in other ways. A shorter barrel on a self defense gun makes it easier to maneuver the gun through the hallways of home during a home defense scenario, and harder for an attacker to grab on to the end of the gun to try and take it away from its rightful owner. Shorter barrels also make a gun easier to conceal, which is a major consideration when it comes to concealed carry.
Effect of barrel length on bullet velocity
Generally speaking, all other things being equal a longer barrel will produce a higher muzzle velocity for bullets (or other projectiles such as shotgun pellets). That is because the longer barrel gives the burning gun powder more time to accelerate the bullet to a higher speed. Eventually there are diminishing returns when it comes to barrel length (e.g. a handgun with a 50″ barrel would likely lose muzzle velocity due to friction between the bullet and barrel), but that is not a concern in real life as manufacturers don’t tend to produce such absurd barrel lengths.
Effect of barrel length on noise
Because a longer barrel allows for more complete gun powder combustion to occur before the bullet exits the barrel, a longer barrel will generally make for a quieter gun. The noise difference between my Browning BT-99 with its very long barrel is quite noticeable compared to my Remington 870, with its barrel that is just over the minimum length required by law. An even more extreme example is my Kel-Tec PLR-16, which is incredibly loud due to its short barrel. Indeed, in the case of the PLR-16, the still-burning gun powder makes quite a visible spark as it exits the muzzle, with a sound to match.
Effect of barrel length on accuracy
A longer barrel will generally produce a more accurate firearm, at least when using the sights that are built in to the barrel. That is because a longer sighting plane (the distance between the front and rear sights that that the shooter lines up) makes it easier for the shooter to tell if the gun is aimed at the target. Generally, there is a sight near the back of the barrel and near the front of the barrel, and therefore the longer the barrel the greater the distance between those sights, and the more accurate the gun will be aimed by the shooter. Such a consideration doesn’t apply if a telescopic or red-dot sight is used.
Effect of barrel length on recoil
All other things being equal, a longer barrel will produce a firearm that has less recoil, because the longer barrel adds to the weight of the firearm. A heavier firearm will have less recoil than a lighter firearm. Often, the recoil difference between a gun with a barrel length that is just an inch or so longer or shorter will not be enough to make a significant difference in weight (or recoil).