Firearm Materials & Service Life

There are many options for materials used in today’s modern firearms. As metallurgical science has improved, so too has the number of materials used in firearm construction. These materials can affect the service life of the firearm and how the firearm will hold up to years of use; or abuse in some cases. For this week’s article I will focus on common materials used, how they affect the longevity of a firearm, and how environmental and maintenance factors affect service life; as well as how different finishes can affect the life of the firearm. 

There are many different alloys being used in modern firearm construction. Some of these have been in use for decades, some are new to the production game, while others are proprietary compounds from individual companies. The most popular material used in firearms is 4140 ordinance steel. This type of material is used “in barrels, bolts receivers and high-stress items like muzzle brakes.” (Sweeney, 2022) This alloy material is known for its toughness, ductility, and good resistant qualities against abrasive wear, corrosion, and heat; it is also capable of being tempered and heat treated to increase hardness. Its material composition is the following: 

Element

Content

Carbon, C

0.380 - 0.430 %

Chromium, Cr

0.80 - 1.10 %

Iron, Fe

96.785 - 97.77 % (As remainder)

Manganese, Mn

0.75 - 1.0 %

Molybdenum, Mo

0.15 - 0.25 %

Phosphorous, P

≤ 0.035 %

Silicon, Si

0.15 - 0.30 %

Sulfur, S

≤ 0.040 %

(AZO Materials, 2012)

In addition to this material you can also find firearms featuring 4150; a harder, more durable, and more expensive variety of 4140, 3310 Carpenter 158 steel, 416 stainless steel, 6061 & 7075 Aluminum, and Titanium-cobalt alloys to name a few. (Sweeney, 2022) There are many more depending on the firearm part and its use on the firearm. Some parts such as a trigger guard may be from a softer alloy material. Plastics, ceramics, carbon fibers, fiber glass, and other materials have all become more popular over the years as well. (NRA Staff, 2019) 

Due to its light weight and corrosion resistance, Aluminum alloys have become much more popular as well. Some of the benefits of Aluminum alloys is the weight reduction, up to 30% to 60% compared to steel alloys, and affordability. Though, durability is also reduced when compared to steel due to aluminum’s lower tensile strength. (Clinton Aluminum, 2017)

These materials can all affect the service life of the firearm. How much they affect the longevity depends heavily on many factors. Under perfect conditions, it’s possible for a firearm to last centuries or longer, but, of course, rarely does a firearm find itself in such a position. The major factors that affect service life are “intensity”, “exposure”, and “maintenance”. (Halek, 2017) “Intensity” refers to the repeated use of the firearm and the abuse it may sustain from frequent usage. “Exposure” refers to the environmental conditions such as heat and humidity and the length of time they are in contact with these elements. “Maintenance” refers to the regular care the weapon is given before, during, and after usage. The materials mentioned previously come into play when determining how they will stand up to these three factors. 7075 aluminum will handle exposure to a humid environment differently than 4140 steel. As Halek states in his article How Long Will Your Handgun Last, “No matter how well or poorly engineered a firearm may be, if it is routinely exposed to the elements (salt water, high humidity, etc.) and used in an intense manner over a length of time, some component in that handgun will break”; however, “If you store your handgun in a safe, relatively dry, non-humid environment, fire about 500 rounds a month through it, and clean it after every use, that handgun will last you the rest of your natural life.” (Halek, 2017)

Firearm finishes can also play an important part in the service life of a firearm. Some methods of firearm finishing are more durable than others. The most common type and industry standard of firearm finishes is hot-caustic bluing. Applying a finish to the firearm certainly extends the life of the firearm. One of the most durable finishes popular on the market today is Cerakote; which claims to be the “strongest and most durable” finish available. It is a ceramic coating that is “rust-proof, self-lubricating, scratch-resistant, and solvent resistant,” as well as abrasive resistance. (Double Tap Designs) Such finishes protect the firearm from the afore mentioned factors that most drastically affect durability. 

Bibliography

AZO Materials. “AISI 4140 Chrome-Molybdenum High Tensile Steel.” AZoNetwork.  July 5th, 2012. https://www.azom.com/article.aspx?ArticleID=6116.

Clinton Aluminum. Aluminum Alloys Used In Guns. March 17th, 2017. 

 Double Tap Designs. Frequently Asked Questions. 

Halek, G. “How Long Will Your Handgun Last?” Concealed Nation. February 27th, 2017. https://concealednation.org/2017/02/how-long-will-your-handgun-last/.

NRA Staff. “What Is the Best Gun Barrel Material?” NRA Family. December 31st, 2019. https://www.nrafamily.org/content/what-is-the-best-gun-barrel-material/.

Sweeney, Patrick. “What Makes Premium Gun Metal? Breaking Down Gun Metal Basics.” Rifle Shooter. July 25th, 2022. https://www.rifleshootermag.com/editorial/guide-to-gun-metal/83987.