15 Common Mossberg Sa-20 Problems (With Fixes!)

Hi dear visitor welcome to our blog. If you are facing a problem with your Mossberg SA-20. 

So Don’t worry about it. This is a common thing. 

In this guide, we explain 15 common problems of this model with unique solutions.

Mossberg Sa-20 Problems

Inconsistent Ejection


The inconsistent ejection issue in the Mossberg Sa-20 is often a result of dirt and grime accumulation in the ejection port. 

Over time, particles can build up and interfere with the smooth operation of the ejection mechanism. 

This can lead to a failure in the ejection of spent shells, thereby disrupting your shooting experience.


To resolve this issue, a thorough cleaning of the ejection port is recommended. Use a suitable gun-cleaning solvent and a soft brush to gently remove any buildup. 

After cleaning, ensure to lubricate the mechanism to facilitate smoother operation. 

Regular maintenance and cleaning can significantly reduce the likelihood of inconsistent ejection, ensuring a more reliable performance from your Mossberg Sa-20.

Difficulty with loading


The common cause of loading difficulties in the Mossberg SA-20 is often linked to the ammunition feed mechanism. 

The firearm’s feed latch or magazine tube could be faulty, causing the shotgun to jam or misfeed when loading shells. 

The condition of the shells themselves can also influence the loading process; dented or deformed shells may cause loading issues.


The solution to alleviate loading difficulties can vary based on the cause. If the issue is with the firearm’s feed mechanism, it may require cleaning or replacing the specific parts responsible for the problem. 

If the issue is related to the shells, ensuring the use of undamaged, high-quality shells can help. 

Regular maintenance and cleaning of the firearm after use is a preventive measure that ensures smooth loading and operation.

Poor Cycling of Shells


The poor cycling of shells in a Mossberg SA-20 can be due to a variety of reasons. One of the most common causes is the use of low-quality or incorrect types of ammunition. 

This can lead to inadequate pressure, resulting in failure to eject spent shells and load new ones. Additionally, an overly dirty or improperly lubricated gun can also contribute to cycling problems.

Remember: Incorrect ammunition and poor maintenance are common causes of cycling issues.


Resolving the cycling issue primarily involves addressing its causes. Switch to high-quality, appropriate ammunition for your Mossberg SA-20. 

This ensures proper pressure for cycling. Secondly, regular and thorough cleaning of the gun is essential. 

Make sure to properly lubricate the moving parts to ensure smooth operation. In severe cases, consider getting a professional gunsmith to inspect and repair your firearm.

Keep in mind: Using appropriate ammunition and regular maintenance can mitigate cycling problems.

Trigger Assembly Issues


One common issue experienced by users of the Mossberg SA-20 is a malfunction in the trigger assembly.

This problem often arises due to the complex nature of the trigger’s internal mechanisms. Over time, the sear or hammer can wear down, causing the trigger to lose its crispness or even fail to fire.

Key factors: Complex internal mechanisms and wear over time can cause trigger malfunctions.


Addressing this issue usually involves a complete disassembly and thorough examination of the trigger assembly. Worn or damaged parts should be replaced. 

If you’re not comfortable doing this yourself, consider getting help from a professional gunsmith. Regular maintenance can also prevent issues from arising in the first place.

Key takeaway: Regular inspection, maintenance, and professional assistance when needed can keep your Mossberg SA-20 functioning properly.

Misfires or Failure to Fire


The most common reasons for misfires or failure to fire with the Mossberg SA-20 could be due to an unclean firearm, faulty ammunition, or an improperly adjusted gas system. 

Dirt and debris can accumulate in the firearm’s vital components making it challenging for the shotgun to function correctly. 

Additionally, faulty ammunition can cause misfires if the primer is not correctly struck or if the quality of the powder is poor. 

Lastly, an improperly adjusted gas system can also lead to misfires.


Regular and thorough cleaning of the firearm is the first step to prevent misfires. This not only removes the dirt and debris but also ensures all moving parts function smoothly. 

Secondly, always use high-quality ammunition from reliable manufacturers to avoid faulty ammunition. 

Finally, if misfires persist, consider having the gas system checked and adjusted by a professional gunsmith. 

Proper adjustment of the gas system ensures that the right amount of gas is used to cycle the shotgun, therefore reducing the chances of misfires.

Erratic Shot Patterns


Erratic shot patterns in the Mossberg SA-20 may be caused by a variety of issues. Misalignment of the shotgun’s sights, a common issue, can lead to shots veering off the intended path. 

Another potential cause could be the use of incompatible or low-quality ammunition, which can result in inconsistent shot patterns. 

Wear and tear on the shotgun, particularly the barrel, can also compromise accuracy over time.


Resolving erratic shot patterns involves addressing the underlying causes. Regular maintenance and inspection of your shotgun can help catch and correct problems like sight misalignment or barrel damage. 

Using ammunition recommended by the manufacturer ensures compatibility and consistent performance. 

Lastly, consider professional gunsmithing services for advanced issues, as they have the necessary expertise and equipment to restore your Mossberg SA-20 to optimal functionality.

Inadequate Shell Extraction


In some cases, the Mossberg SA-20 might face problems with inadequate shell extraction, primarily because of the buildup of dirt or fouling in the extraction mechanism, or due to some mechanical fault. 

These issues can interfere with the firearm’s ability to properly eject spent shells, causing a delay or complete failure in the extraction process.

A key point to remember: Regular maintenance and cleaning are crucial to prevent dirt or fouling buildup, which can lead to inadequate shell extraction.


To troubleshoot this problem, start with a thorough cleaning of the firearm, focusing particularly on the extraction mechanism. 

Use a good quality gun cleaner and ensure all parts are free from dirt or debris. 

If the problem persists, it might be a mechanical fault, which may require professional assistance. Replacement of faulty parts could be necessary in some cases.

A key point to remember: Regular inspection of the gun parts, especially the extraction mechanism, can help identify any mechanical faults early, preventing inadequate shell extraction.

Barrel Overheating


Overheating typically occurs when the SA-20 shotgun is used excessively without giving it time to cool down. 

This is often a result of rapid-fire shooting, which generates a significant amount of heat in the barrel. 

Prolonged exposure to high temperatures can cause the metal to warp, leading to decreased accuracy and potential damage to the firearm.


To mitigate barrel overheating, users should practice controlled shooting, allowing intervals for the barrel to cool down. 

Furthermore, consider using a barrel cooler, a device designed to expedite the cooling process. 

Regular maintenance and cleaning also play a crucial role in preventing overheating. It’s important to remember that prevention is always better than repair when it comes to firearm longevity and safety.

Difficulty in Disassembly and Reassembly


One of the most common issues that SA-20 users encounter is the complexity involved in disassembling and reassembling the shotgun. 

This problem stems primarily from the shotgun’s intricate design, which includes several small, delicate parts that are not easily accessible.

The disassembly process requires careful attention to prevent any damage or loss of these components. 

The reassembly, on the other hand, can be quite tricky, even for experienced users, due to the precise alignment required for the parts to fit back together correctly.


While Mossberg’s SA-20 may require a learning curve for disassembly and reassembly, there are strategies to mitigate this problem. 

Firstly, it’s advisable to familiarize oneself thoroughly with the user manual before attempting to disassemble the gun. 

This will provide a clear understanding of the gun’s structure and the order in which the parts should be removed and replaced.

Secondly, consider seeking professional help or watching online tutorials to learn the process. Regular practice will also make the process smoother over time. 

Lastly, always ensure that you have a well-lit, clean, and spacious workspace to keep all the parts organized during the process.

Bolt Assembly Problems


The Bolt Assembly in the Mossberg SA-20 can sometimes face issues due to excessive use or improper maintenance. 

This typically manifests as difficulty in loading or ejecting shells, leading to a decrease in the firearm’s overall performance. 

The most common causes are dirt buildup, rust, or wear and tear on the assembly components.

Proper cleaning and maintenance of the Bolt Assembly can prevent these issues to a significant extent. 

Regular inspection for wear or damage can also ensure early detection of potential problems.


To address Bolt Assembly problems, a comprehensive cleaning and lubrication process is often sufficient. 

For more severe issues like rust or damaged parts, replacement of the assembly or its components may be necessary. 

It’s recommended to consult a professional gunsmith for any serious issues or when in doubt. 

A well-maintained firearm not only ensures safety but also enhances the performance and longevity of the Mossberg SA-20.

Stock Cracking or Breakage


The main reason behind stock cracking or breakage in Mossberg SA-20 shotguns is often linked to the recoil the firearm generates when fired. 

Continuous use without proper handling and maintenance can lead to an overload of pressure on the stock, causing it to crack or break.


The ideal solution to this issue lies in regular maintenance and proper handling of the firearm. It’s recommended to frequently check the firearm for any signs of wear and tear. 

Use absorbent materials to manage the recoil effectively, and always handle the shotgun with care to prevent any undue pressure on the stock. 

If the stock has already cracked or broken, consider seeking professional help or replacing the stock altogether.

Uncomfortable Recoil


The uncomfortable recoil of the Mossberg Sa-20 is often caused by its lightweight design, which while providing ease of handling, does not absorb the impact of the shot as effectively as heavier firearms. 

This can result in a more pronounced recoil that may be uncomfortable for some users, particularly those who are new to shooting.

The lightweight design, while beneficial in terms of portability, can lead to greater felt recoil. 

This can be an issue, particularly for inexperienced or smaller-bodied shooters who may struggle with the impact.


A potential solution to this problem could be the use of recoil pads which are designed to absorb a portion of the recoil’s force, making the shooting experience more comfortable. 

Additionally, the practice may help shooters acclimatize to the recoil, and certain shooting stances can also minimize the perceived impact.

The use of recoil pads can greatly reduce the felt recoil, making the shooting experience more comfortable for the user

With practice and proper shooting stances, the user can further minimize the perceived impact of the recoil.

Irregular Feed Mechanism


The irregular feed mechanism in the Mossberg Sa-20 can often be attributed to the wear and tear of the shotgun’s internal components. 

Over time, excessive use can lead to the degradation of these parts, causing inconsistent feeding of shells. 

It’s crucial to periodically check the condition of the internal components to prevent such issues from arising.


The solution to this problem primarily involves regular maintenance and, if necessary, replacing the worn-out parts. 

Implementing a consistent cleaning schedule can prevent the accumulation of residue that may interfere with the feeding mechanism. 

If the issue persists despite regular maintenance, consider consulting with a professional to assess the need for part replacement. It’s always recommended to use high-quality replacement parts for longevity and optimal performance.

Unreliable Safety Mechanism


One of the most commonly reported problems with the Mossberg SA-20 shotgun is an unreliable safety mechanism. 

The safety mechanism is unusually stiff and difficult to engage or disengage, which can lead to dangerous situations if it malfunctions in a critical moment. 

This issue may be due to the design of the gun, the quality of materials used, or inadequate quality control during manufacture.

However, it’s crucial to note that a malfunctioning safety mechanism can be a significant safety hazard, especially in high-stress situations.


The solution to this problem could be a simple replacement of the safety mechanism. It is recommended to consult with a professional gunsmith or the Mossberg customer service team for guidance. 

Additionally, a regular maintenance routine can help prevent future issues with the safety mechanism, ensuring it remains in optimal working condition.

Remember, the safety of the user should always be the top priority when using firearms. A well-maintained and reliable safety mechanism is fundamental to this end.

Inaccurate Sights Alignment


The problem of inaccurate sight alignment in Mossberg Sa-20 is often due to improper gun assembly or physical damage to the sight. 

Over time, rough handling or falls can knock the sight out of alignment. 

Also, if the gun has not been properly assembled, the sight could be incorrectly aligned right from the start, causing targeting and accuracy issues.

The most common causes are improper assembly and physical damage. Regular checks and maintenance can help mitigate this problem.


Correcting the sight alignment involves carefully adjusting the sight to the correct position. This can be done manually, though it often requires a certain level of expertise. 

If manual adjustment doesn’t rectify the problem, consider consulting a professional gunsmith or contact Mossberg customer support.

Always ensure that sight adjustments are made carefully, and consider professional assistance if problems persist.


In conclusion, the Mossberg SA-20, while largely reliable and efficient, does present certain challenges that may pose a disadvantage for some users. 

One such issue is the inaccurate sight alignment that may affect the accuracy and precision during use. It’s vital for users to be aware of this and take necessary precautions or corrective measures, such as regular checks and adjustments. 

Despite this minor setback, the SA-20 remains a popular choice among firearms enthusiasts for its overall performance, durability, and affordability. 

However, as with any equipment, understanding and managing its limitations is key to optimizing its use.


Is the Mossberg SA-20 any good?

Yes, the Mossberg SA-20 is a reliable and affordable choice, well-regarded for its performance and durability despite some minor issues, such as inaccurate sight alignment.

Is the Mossberg SA-20 gas or inertia?

The Mossberg SA-20 operates on a gas system, providing a smooth and reliable cycling of rounds.

What is the problem with the Mossberg SA 410?

The Mossberg SA 410, similar to the SA-20, may suffer from issues with sight alignment, impacting the accuracy of shooting.

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