gun barrels

Cryogenic Treatment for Gun Barrels


Nitrofreeze® provides cryogenic treatment services for the barrels of handguns, rifles, and shotguns, including double barrel shotguns and rifles with .50 caliber barrels. Cryogenic treatment reduces stresses and imperfections in the metal’s microstructure for faster muzzle velocity and tighter shot groupings. This one-time, permanent process also increases wear resistance for easier barrel cleaning and reduces heat, friction and barrel wear for extended life.

From the moment the metal for a future gun barrel changes from a molten state to a solid form, material stresses are locked-in. Heat treatment and machining processes also impart residual stresses that can affect accuracy and performance. That’s why Nitrofreeze® offers a proprietary, stress-relieving cryogenic treatment process with ultra-slow ramp rates and stabilization stops, the industry’s longest holds at -300°F, and a minimum 24-hour dwell at temperature.

Keep reading to learn more, or contact us for a quote.

Heat Treatment, Machining and Gun Barrel Stresses

Today, most gun barrels are made of steel, metals with varying amounts of carbon, iron, and other alloying ingredients. Before machining occurs, formed steel is heat-treated to a specific temper to impart the required mechanical properties, which can vary by firearm. For example, according to the Defense Systems Information Analysis Center (DSAIC), “rifle barrels launching heavier projectiles require more stringent material properties than handguns launching lighter projectiles.”

After steel is heat treated, a percentage of retained austenite remains, and there are microscopic voids in the metal’s micro-structure. This makes the austenite less desirable than martensite, which also has a crystalline structure but is both very hard and very strong. After tempering is complete, machining in the form of boring and reaming introduces additional stresses that remain even in the absence of external loading and thermal gradients.

If these locked-in stresses are not removed, warping and distortion can occur when the gun is fired and the barrel heats up. Firearms that are produced from castings and forgings that cool at different rates are also subject to temperature-related issues. Fatigue failure, the formation and propagation of cracks due to repetitive or cyclic loads, is a risk as well. Fortunately, Nitrofreeze® offers a stress-relieving solution with examples like these that we’ve documented.

Cryogenic Treatment and Gun Barrel Stress Relief

During cryogenic treatment, Nitrofreeze® uses liquid nitrogen to reduce the temperature of the gun barrel to -300° F. The barrel is then maintained at this cryogenic temperature for a minimum of 24 hours. This carefully-controlled process causes carbon particles to precipitate from the metal as carbides. In turn, these carbides form a lattice structure that fills microscopic voids in the metal. The result is a denser, smoother surface for reduced friction, heat, and wear.

Metallurgically, cryogenic treatment for gun barrels promotes the additional transformation of retained austenite into martensite. The precipitation of eta-carbides, submicroscopic carbides that are brilliant white or black in color, can be observed with scanning electron microscopy (SEM). Overall, the benefits of cryogenic treatment for gun barrels include increased durability, improved wear resistance, and reduced fatigue failures.

Choose Nitrofreeze Cryogenic Treatment for Gun Barrels

Nitrofreeze® cryogenic treatment is a quality-driven metal enhancement process from start to finish. From the time your gun barrel arrives at our facility through final inspection, trained technicians ensure the success of your project. Nitrofreeze® validates all our cryogenic treatment cycles to determine that all process parameters have been met and includes a statement of compliance with all standard orders. For a nominal fee, we can also provide you with a Certificate of Compliance.

To get started, contact us at the phone number and email listed below for a free consultation.

(508) 45907447 x105 |