What is a gun barrel?
A gun barrel is a very essential component of a wide range of gun type ammunition like air guns, small firearms or even heavy military ranged weapons. It is majorly a metal tube through which bullets or other similar masses are accelerated to a high velocity by converting the already stored chemical energy into kinetic energy.
This energy conversion usually occurs through heated, quickly expanding propellant gases. While it may seem a very simplified version, a great deal has gone into solving the complex relationship of chemistry and physics using metallurgy, engineering science, and ballistics.
The role of a gun barrel
When it comes to firearms, gun barrels greatly impact the overall design features like length, weight and recoil. The balance, swing, pointing and other handling qualities of the firearms are strongly influenced by the gun barrel. In rifles and handguns, barrel control accuracy to a large extent. In shotguns, the barrel governs the tightness and the quality of the pattern.
Components of a gun barrel:
However, in revolvers, the chamber comes as a part of the gun’s cylinder independent of the barrel. This cylinder has multiple chambers which rotate in turns to align with the barrel. Chamber further comprises three parts, namely the border, shoulder and the neck.
The Bore is the tubular structure of the barrel, and comprises the whole length of the barrel. Prior to firing, the bore enables the projectile (bullet, shot or any other mass) to gain speed and kinetic energy. Some modern firearms may have helical grooved bores structures, to enhance the speed, as opposed to the smoothbore guns.
The front part of the gun from where the projectile finally exits is called muzzle. Since the muzzle forms the last point of contact between the barrel and the projectile, it determines the accuracy to a great extent. Any inconsistency in gaps between the muzzle and the projectile, can cause the projectile to deflect from its desired path. The muzzle can also act as a detachable part, to allow attaching different accessories.
Choosing the right Barrel
There are a few factors one need to consider while choosing the right kind of barrel, some of them being the following:
- Size of the Barrel
Size of the barrel dominantly is the length of the tubular structure. With simple logic, longer the barrel, more is the weight. While a longer and heavier barrel may provide a better swing, a shorter and lighter barrel is more comfortable to carry. Also, the longer barrel aids in a better precision than a shorter one when it comes to long distances.
- Material options
Before the 1880s, gun barrels were usually made of alloys of brass or iron. However, its use was discontinued when the market switched to smokeless propellants after 1885.
This is when new steel alloys came into use as they provide advantages of easy availability, easy to make, great strength, factor toughness, hardness, resistance to heat and shock etc. Some of the suitable material options for gun barrels include:
- Alloy steels
With an excellent balance of strength and cost, alloy steel barrels are widely used all over the world. The alloys contain varying quantities of metals like chromium, nickel, manganese etc. to improve the quality and achieve the desired properties.
- Stainless steel
It is quite resistant to heat corrosion and humidity corrosion. Stainless steel alloys like 416R are popular for easy manufacturing. Also, stainless steel barrels are more expensive than the ones made of alloy steel, due to high cost of raw material.
With comparable physical characteristics to stainless steel, columbium may be used to make barrels with increased resistance to heat erosion and corrosion but it is quite an expensive choice of material (due to its unavailability) and hence not a very popular one.
Aluminum barrels accompanied with steel liner can be used. However, Aluminum is a very light metal and is inferior to steel in terms of strength and resistance to heat erosion, which makes it unusable without steel liner.
With the comparable strength, titanium-cobalt alloys if used are capable of reducing the weight to more than half of what steel alloys offer. However, due to its high cost and difficulty in production, it is not a popular choice.
- Carbon Fiber
Carbon-fiber can be used as an outer shell accompanied with stainless steel liner. It is good in rigidity and natural vibration damping. Though expensive, it is widely used for ultra-lightweight rifles due to its excellent properties.
Fiberglass is inexpensive and widely available can be combined with steel liner to get best results. However, it is being replaced with carbon fiber despite its good strength and resistance to heat.
- Other Options
New materials with potential include metal-matrix composites, ceramics and other engineered metal alloys.
Not only does contour affect the looks of the finished firearm but it also affects the performance. Heavier contour may take more time to heat up and cool off eventually, but help in reducing the recoil of the gun.
Thinner contours though lightweight and they cool off easily, but the tendency to jump around is a lot more. Medium contour may be a good preference if any specific result is not required.
The rate of spin of the bullet in the gun barrel is called twist rate. It is measured in inches per turn. An adequate twist rate is crucial to stabilize the bullets being shot. Insufficient twist rate may lead to inaccuracy or even cause the bullet to drift.
Lining options vary from steel lining, stainless steel lining to chrome lining. As discussed above, steel and stainless lining may be used to accompany materials like aluminum and carbon fiber to achieve high stability and strength.
Although difficult to apply, and leading to less accuracy, chrome lining gets more preference in case of rapid shooting as it is easier to clean.
Though there is a large variety of barrel types available in the market based on the above options, one needs to select the best combination of features as per his/her own requirements.
All the above factors must not be seen in isolation but together to comprehend a perfect solution for your needs.