Hey guys! If you're experiencing issues with your Mossberg 940 Pro Tactical, you're in the right place. This shotgun is known for its reliability and performance, but like any firearm, it can sometimes run into problems. Let's dive into some common issues and how to resolve them, ensuring your 940 Pro Tactical stays in top-notch condition. Whether it's cycling issues or something else, we'll get you sorted!

Common Problems with the Mossberg 940 Pro Tactical

The Mossberg 940 Pro Tactical is designed to be a high-performance shotgun, but several common issues can affect its reliability. Understanding these problems is the first step in troubleshooting and resolving them. Let's explore these issues in detail.

Cycling Issues

Cycling problems are among the most frequently reported issues with the Mossberg 940 Pro Tactical. These can manifest in several ways, such as failure to feed, failure to eject, or stove-piping. Several factors can contribute to these malfunctions, including ammunition type, cleanliness, and gas system issues.

• Ammunition Type: The Mossberg 940 Pro Tactical is designed to cycle a wide range of ammunition, but it may not reliably cycle very light loads or low-recoil shells. Using the correct type of ammunition is crucial for reliable cycling. High-brass shells or those specifically designed for semi-automatic shotguns often perform best.
• Cleanliness: A dirty firearm is a common cause of cycling problems. Carbon buildup and debris can accumulate in the action and gas system, hindering the shotgun's ability to cycle correctly. Regular cleaning and lubrication are essential for maintaining optimal performance. Pay close attention to the gas ports, piston, and action when cleaning.
• Gas System Issues: The gas system regulates the amount of gas used to cycle the action. If the gas system is not functioning correctly, it can lead to cycling problems. Ensure that the gas piston and gas ports are clean and free of obstructions. Some models may have adjustable gas systems, so ensure they are correctly set for the ammunition you are using.

To address cycling issues, start by thoroughly cleaning the shotgun, paying particular attention to the gas system. Then, test the shotgun with different types of ammunition to see if a particular load is causing the problem. If the issue persists, further inspection of the gas system components may be necessary.

Failure to Feed

Failure to feed occurs when a new shell does not properly load into the chamber after firing. This can be caused by several factors related to the magazine tube, the shell latch, or the action itself. Ensuring each of these components is functioning correctly is critical for reliable feeding.

• Magazine Tube Issues: The magazine tube must feed shells smoothly into the action. If the magazine tube is dirty, dented, or has a weak spring, it can cause feeding problems. Ensure the magazine tube is clean and free of any obstructions. Check the magazine spring for proper tension and replace it if it is weak.
• Shell Latch Problems: The shell latch is responsible for releasing shells from the magazine tube into the action. If the shell latch is worn, damaged, or not functioning correctly, it can cause failures to feed. Inspect the shell latch for wear or damage and replace it if necessary. Ensure it moves freely and engages properly.
• Action Issues: Problems within the action itself can also lead to failures to feed. This can include issues with the bolt, the carrier, or the timing of the action. Ensure that all components of the action are clean, properly lubricated, and moving freely. If there are any signs of damage or excessive wear, these parts may need to be replaced.

Addressing failure to feed issues involves a detailed inspection of the magazine tube, shell latch, and action. Cleaning, lubricating, and replacing worn parts can often resolve these problems, ensuring smooth and reliable feeding.

Failure to Eject

Failure to eject happens when the spent shell casing isn't fully expelled from the shotgun after firing. This malfunction can significantly slow down follow-up shots and can be caused by issues with the extractor, ejector, or the ammunition itself.

• Extractor Problems: The extractor is responsible for pulling the spent shell casing from the chamber. If the extractor is worn, broken, or dirty, it may fail to grip the shell casing properly. Inspect the extractor for damage and ensure it is clean and free of debris. A weak or damaged extractor spring can also cause ejection problems, so check and replace it if necessary.
• Ejector Issues: The ejector is responsible for kicking the spent shell casing out of the shotgun. If the ejector is worn, damaged, or not properly aligned, it can cause failures to eject. Inspect the ejector for any signs of damage and ensure it is correctly positioned. Replace the ejector if necessary.
• Ammunition Problems: In some cases, ammunition can be the cause of ejection problems. Shells that are damaged, improperly sized, or have weak crimps can cause ejection failures. Try using different brands or types of ammunition to see if the problem persists.

Resolving failure to eject issues involves checking the extractor, ejector, and ammunition. Regular maintenance and using quality ammunition can help prevent these issues, ensuring reliable ejection every time.

Light Primer Strikes

Light primer strikes occur when the firing pin does not strike the primer with enough force to ignite the powder. This can result in a failure to fire, even though the shotgun appears to be in battery. Several factors can contribute to light primer strikes, including firing pin issues, hammer spring problems, and ammunition issues.

• Firing Pin Problems: The firing pin must be clean, free of damage, and able to move freely within its channel. If the firing pin is dirty or damaged, it may not be able to strike the primer with sufficient force. Clean the firing pin and its channel thoroughly, and replace the firing pin if it is damaged.
• Hammer Spring Issues: The hammer spring provides the force that drives the firing pin forward. If the hammer spring is weak or broken, it may not generate enough force to ignite the primer. Replace the hammer spring if it is weak or broken.
• Ammunition Issues: Some ammunition may have hard primers that require a stronger strike to ignite. If you are experiencing light primer strikes with a particular brand of ammunition, try using a different brand with softer primers. Also, ensure that the ammunition is stored properly to prevent moisture damage, which can affect primer performance.

Addressing light primer strikes involves inspecting the firing pin, hammer spring, and ammunition. Regular maintenance and using quality ammunition can help prevent these issues, ensuring reliable ignition.

Magazine Tube Capacity Issues

Some users have reported issues with the magazine tube not holding the advertised number of shells. This can be due to variations in shell length, magazine spring tension, or manufacturing tolerances. Ensuring the magazine tube is correctly configured and maintained can help maximize its capacity.

• Shell Length Variations: Different brands and types of shotgun shells can vary slightly in length. This can affect the number of shells that can be loaded into the magazine tube. Use shells of consistent length to maximize capacity.
• Magazine Spring Tension: The magazine spring must have sufficient tension to feed shells reliably. If the spring is weak, it may not be able to push the shells far enough forward, reducing the magazine's capacity. Replace the magazine spring if it is weak.
• Manufacturing Tolerances: Slight variations in manufacturing can affect the internal dimensions of the magazine tube. If the magazine tube is not perfectly sized, it may not hold the advertised number of shells. Contact the manufacturer if you suspect a manufacturing defect.

To address magazine tube capacity issues, ensure that you are using shells of consistent length, check the magazine spring tension, and inspect the magazine tube for any defects. Regular maintenance and using quality components can help ensure that the magazine tube performs as expected.

Troubleshooting Steps

When you encounter a problem with your Mossberg 940 Pro Tactical, a systematic approach can help you identify and resolve the issue efficiently. Here are some steps to guide you through the troubleshooting process:

1. Start with a Clean Firearm: Before diagnosing any problem, ensure your Mossberg 940 Pro Tactical is thoroughly cleaned. Remove any carbon buildup, debris, and old lubricant that could be affecting its performance. Focus on cleaning the gas system, action, and magazine tube. A clean firearm is less likely to experience malfunctions.
2. Check Ammunition: Ammunition can often be the culprit behind cycling and feeding issues. Ensure you are using the correct type of ammunition for your shotgun. Avoid using very light loads or low-recoil shells, as they may not cycle reliably. Try different brands and types of ammunition to see if the problem persists with specific loads. High-quality ammunition can make a significant difference in performance.
3. Inspect the Gas System: The gas system is critical for the Mossberg 940 Pro Tactical's operation. Ensure that the gas piston and gas ports are clean and free of obstructions. Some models have adjustable gas systems, so make sure they are correctly set for the ammunition you are using. A properly functioning gas system ensures reliable cycling.
4. Examine the Extractor and Ejector: Failures to eject are often caused by issues with the extractor or ejector. Inspect the extractor for damage and ensure it grips the shell casing properly. Check the ejector for proper alignment and function. Replace any worn or damaged parts to ensure reliable ejection.
5. Check the Firing Pin and Hammer Spring: Light primer strikes can be caused by a dirty or damaged firing pin or a weak hammer spring. Clean the firing pin and its channel thoroughly, and replace the firing pin if it is damaged. Replace the hammer spring if it is weak. A properly functioning firing pin and hammer spring are essential for reliable ignition.
6. Inspect the Magazine Tube: Feeding issues can often be traced to the magazine tube. Ensure the magazine tube is clean and free of any obstructions. Check the magazine spring for proper tension and replace it if it is weak. Make sure the shell latch is functioning correctly and releasing shells smoothly into the action. A properly maintained magazine tube ensures reliable feeding.
7. Test and Observe: After performing maintenance or replacing parts, test the Mossberg 940 Pro Tactical at the range. Observe its performance closely, paying attention to any malfunctions. Note the specific conditions under which the problems occur, such as the type of ammunition used or the frequency of the issue. This information can help you further diagnose the problem.

By following these troubleshooting steps, you can systematically identify and resolve common issues with your Mossberg 940 Pro Tactical, ensuring it remains a reliable and high-performing firearm.

Maintenance Tips

Regular maintenance is key to keeping your Mossberg 940 Pro Tactical in optimal condition. A well-maintained shotgun is more reliable, accurate, and enjoyable to shoot. Here are some essential maintenance tips to help you care for your firearm:

• Regular Cleaning: Clean your Mossberg 940 Pro Tactical after each use, or at least after every few hundred rounds. Use a quality gun cleaning solvent to remove carbon buildup, powder residue, and fouling from the bore, action, and gas system. Pay special attention to the gas ports, piston, and bolt face. A clean firearm operates more smoothly and reliably.
• Proper Lubrication: Lubrication is essential for reducing friction and wear on moving parts. Apply a light coat of gun oil to the bolt, action, and other critical components. Avoid over-lubrication, as excess oil can attract dirt and debris. Use a high-quality gun oil that is designed for firearms.
• Gas System Maintenance: The gas system requires special attention to ensure proper functioning. Disassemble the gas system components, including the gas piston and gas ports, and clean them thoroughly. Use a brush or pick to remove any carbon buildup. Ensure that the gas ports are clear of obstructions. A clean gas system ensures reliable cycling.
• Magazine Tube Care: The magazine tube should be cleaned and inspected regularly. Remove the magazine spring and follower, and clean the inside of the tube with a brush. Inspect the magazine spring for any signs of wear or damage, and replace it if necessary. Ensure that the shell latch is functioning correctly and releasing shells smoothly. A well-maintained magazine tube ensures reliable feeding.
• Check Springs Regularly: Springs are critical components in the Mossberg 940 Pro Tactical, and they can lose tension over time. Regularly check the magazine spring, hammer spring, and other springs for signs of wear or weakness. Replace any springs that are not performing as they should. Fresh springs ensure reliable operation.
• Inspect for Wear and Damage: Periodically inspect all components of your Mossberg 940 Pro Tactical for signs of wear, damage, or corrosion. Pay attention to the bolt, extractor, ejector, and firing pin. Replace any parts that are worn or damaged to prevent malfunctions. Regular inspection can catch potential problems before they cause issues.
• Proper Storage: Store your Mossberg 940 Pro Tactical in a safe and dry location. Use a gun case or gun safe to protect it from dust, moisture, and unauthorized access. Apply a light coat of oil to prevent rust and corrosion. Proper storage helps prolong the life of your firearm.

By following these maintenance tips, you can keep your Mossberg 940 Pro Tactical in excellent condition and ensure its reliability and performance for years to come.

Upgrades and Modifications

Enhance your Mossberg 940 Pro Tactical with various upgrades and modifications to improve its performance and handling. Many aftermarket parts are available to customize your shotgun to your specific needs. Here are some popular upgrades and modifications:

• Improved Sights: Upgrading the sights on your Mossberg 940 Pro Tactical can improve accuracy and target acquisition. Options include fiber optic sights, ghost ring sights, and red dot optics. Choose sights that are appropriate for your shooting style and intended use. Improved sights can enhance your shooting experience.
• Enhanced Trigger: An enhanced trigger can provide a smoother, lighter, and more consistent trigger pull. This can improve accuracy and reduce the risk of jerking the gun during firing. Several aftermarket triggers are available for the Mossberg 940 Pro Tactical. A better trigger can improve your shooting performance.
• Extended Magazine Tube: An extended magazine tube can increase the capacity of your Mossberg 940 Pro Tactical, allowing you to load more shells. This can be particularly useful for competition shooting or tactical applications. Ensure that the extended magazine tube is compatible with your shotgun and complies with any applicable regulations. More capacity can be advantageous in certain situations.
• Aftermarket Stocks and Grips: Aftermarket stocks and grips can improve the ergonomics and handling of your Mossberg 940 Pro Tactical. Options include adjustable stocks, pistol grips, and forends with improved texture and grip. Choose stocks and grips that fit your hand and shooting style. Better ergonomics can improve comfort and control.
• Recoil Reduction Systems: Recoil reduction systems can help reduce felt recoil, making the Mossberg 940 Pro Tactical more comfortable to shoot, especially with heavy loads. These systems can include recoil pads, hydraulic buffers, and muzzle brakes. Reducing recoil can improve accuracy and reduce fatigue.
• Shell Carrier Upgrades: Upgrading the shell carrier can improve the speed and ease of reloading. Options include enlarged or modified shell carriers that make it easier to load shells into the magazine tube. Faster reloading can be beneficial in competition or tactical scenarios.

When selecting upgrades and modifications for your Mossberg 940 Pro Tactical, choose high-quality parts from reputable manufacturers. Ensure that any modifications are installed correctly and do not compromise the safety or reliability of your firearm. Properly selected and installed upgrades can enhance your shooting experience and improve the performance of your Mossberg 940 Pro Tactical.

Conclusion

The Mossberg 940 Pro Tactical is a fantastic shotgun, but like all firearms, it can have its share of issues. By understanding these common problems and knowing how to troubleshoot them, you can keep your shotgun running smoothly and reliably. Regular maintenance, proper ammunition selection, and timely repairs are essential for maintaining peak performance. So, keep your Mossberg 940 Pro Tactical clean, well-lubricated, and properly maintained, and it will serve you well for years to come!