The gun manufacturing process is precise and complex, involving specialized metal alloys and engineering. The strength of the gun materials and extensive testing are all essential to the process of producing a reliable and effective gun. There are a few concerns regarding the composite strength of all of the materials. These all involve directional force applied to the metal: compressive force, torsional strength, and tensile strength. In gun production, all of these things are evaluated in stress tests to determine the yield point of the materials–the maximum amount of stress the material can withstand without permanent damage. Here is a look at some standard gun materials and how they affect the gun’s performance.
The foundational material in any gun is steel. High carbon, heat treated steel is the traditional metal used in gun production. The heat treatment scale is quantified by the Rockwell C scale. In pistols, the steel frame is not usually as hard as the slide since it is the feed mechanism and locking mechanism for the barrel. Compression and tensile strength are important factors to test in the steel construction. Recoil in the gun is absorbed by the recoil plate as force is applied to that part of the frame. Here, the tensile strength is simultaneously tested as the frame is stretched by the pressure contained in the cylinder and barrel.
Modern gun construction in the steel phase is more efficient and cost effective when done by computerized machining centers. Because steel is so strong and versatile, it can be manipulated easily into structures and small parts using castings and machine injection molding. The weight of steel makes control and aim more steady and efficient, but also heavier. Steel is easily finished with stainless finish alloys, nickel and chrome plating. This gives the final gun a nice aesthetic and wear and corrosion resistance.
Aluminum framing is one of the most important components in modern guns and can save 35-40% in weight next to steel. The trade off to aluminum framed guns is that they are not as durable as steel and lack the tensile strength. The aluminum alloy, therefore, must be selected carefully for weight balance and grip width for proper ergonomics when fired. Aluminum is a popular alternative to steel for certain guns–certain 9mm pistols, for example–and offers a lightweight, aesthetic look and feel. The lower compression and tensile strength make aluminum frames more susceptible to stress cracking and can often not be repaired when this occurs. The recoil can also be greater in aluminum framed guns.
Polymer plastics was originally used in gun production on non-structural components like recoil spring guides and grips. Plastic was eventually expanded and used in small components and as part of the frame. Many guns today employ polymers in frame production as popular alternatives to traditional steel. Plastic has a number of benefits, including weight savings, damage resistance from recoil impact, and better comfort in a wider temperature range, unlike steel. Plastic frames also allow a certain versatility in interchangeable grip panels for different hand sizes.
Unlike aluminum and steel, however, plastic has low tensile strength and can more easily fail compared to denser, more resistant metal materials. The lighter weight can also compromise aim stability and recoil control, but these depend on the shooter and the specific type of gun. Overall, plastic construction is often cheaper and offers weight savings and corrosion resistance.