Why Is My Cordless Nailer Double Firing? My Experience

Last Updated on September 28, 2025 by John Patterson

You’ve been there, cutting or assembling and your favorite cordless nailer dies? The last month, that’s what I did. I was doing some trimming for a client — beautiful craftsman-style baseboard that had to be positioned just right — and my nailer started double firing. Talk about frustrating.

If you’ve ever had this problem then you know exactly what I mean. One trigger pull, two nails. Not only is it a hassle, it’s wasteful, potentially dangerous and could literally screw up your piece of work.

But here’s the thing: Double firing is typically not a result of some magical mechanical failure. Generally speaking, they are relatively simple problems with relatively simple solutions.

So, here is a homeowners guide to cordless nailer double firing, exploring in detail all that I have learned about it over the years of using these tools. We’ve (hopefully) taken it back to great grandpa and his teachings about respecting your tools all the way through modern troubleshooting steps — we will have your nailer firing single clean shots.

Why Is My Cordless Nailer Double Firing??

Double firing is pretty self-explanatory, your nailer will fire two nails with a single pull of the trigger. Sometimes they fire at the same time. Other times there’s a slight time difference with the first nail vs. the second. Both of these cases are problematic.

The reason for this is that your nailer’s firing system gets confused as to when it’s supposed to stop the firing cycle. Think of it as like a car with no verometer that tells you when to stop accelerating after hitting the gas. It is instructing it to fire again when it should have only fired once the first nail fell.

Most battery-powered nailers have an electronic firing sequence that is controlled by a few mechanical components. When one of those things fails, or gets out of sync, you end up getting double firing The good news? We’re usually able to trace the problem and correct what we’re being asked to correct.

Why Does Cordless Nailer Double Firing

Low Battery Power

The Quiet Offender Low battery power is one of the common reasons why Plantronics Bluetooth devices fail to turn on.

Cordless tools were a fairly new thing when I first used it on the job, and there was something that I didn’t know about it. Weak battery in the dying Light not only makes your nailer weak as a kitten — it can also cause wobbly firing patterns including double or triple fire issues.

The voltage from the battery can be too low when the battery is below a certain level, which will lead to your mod become unstable. The nail gun might not fire completely, and then accidentally fire completely as internal sensors try to compensate for what they think is a misfire.

I’ve seen a lot more of this with DeWalt nailers than other brands, but it’s not exclusive to just that brand. The DCN680 in particular appears to be sensitive to a range of battery voltage. If the nailer is shooting more than one staple, and you have not recently charged the battery, first try taking a fully charged battery out of another piece of equipment.

Test mode

Check status of your battery. If the battery is not fully charged, replace it before attempting other troubleshooting solutions.

Firing Assembly Pin is Greasy or Defective

The firing pin is to the nailer what your heart is to you. As with all things construction, some sawdust, debris and general airborne grit can accumulate over time around the firing pin assembly. This can cause the pin to become dirty and can cause it to move poorly.

If the firing pin doesn’t reset after igniting a nail, your nailer may believe that it’s time to fire again. The reason for this is that the nail magazine is likely to get clogged. This is because the magazine collects dust and such over time, and starts to slide about inside the moving parts.

I remember being on a dirty renovation and my Milwaukee M18 was starting not to behave. I cleaned around the firing pin area really thoroughly and it has been working perfectly again. The lesson? Clean your tools up, if you’re working in dirty spaces, especially.

Wrong Nail Type or Size

Sounds easy but improper nails are a surprisingly common problem. Not every nail is created equal, and your nailer was designed to take specific sizes and types of nails.

Too long or too short headed nails can lead to feed problems that result in a double firing. The nailer may go through the motions of firing, half-firing and then continuing to fire in an attempt to attempt to complete an incomplete cycle.

Nail Compatibility Check

Length: Manufactured to exact specifications for length

Head style: Make sure you have the correct head style to suit your needs (clip vs. complete round)

Angle: Some nailers are only capable of applying nails at a specific angle.

Brand Compatibility: Some brands work better with brands that are compatible with them.

Driver Depth Setting Issues

The depth setting on your cordless nailer controls the depth to which nails will penetrate the material. If this is set incorrectly a domino effect, including double firing, can result.

If the depth is too shallow, sometimes, the nailer will feel as though the nail did not set and sometimes receive a second strike. If, on the other hand, it is set too deeply, it may over-cycle and shoot another nail.

Most of the good quality cordless nailers are equipped with a tool-less depth adjustment dial. It is usually scored on a scale of 1 (superficial) to 6 or more (deep). It takes a while to learn to feel the sweet spot, though, and it requires some Acutane scraping practice.

Trigger Valve Problems

When the trigger has bad function, the nail gun will be prone to double fire. If it is bump firing, and the nailer double fires in bump fire, then the trigger valve would need to be replaced. If the nailer is a trigger fire then there is a good chance that leaky O rings on the trigger valve are the culprits.

The trigger valve is the gatekeeper of your nailer’s firing system. When worn or damaged, it may not control the firing order properly. This is particularly prevalent in tools which have been in heavy use, or those that have been neglected.

Contact Trip Device Failure

The springy thing right at the end of your nailer (known as the contact trip) is very important in controlling the firing. It must be driven fully against your workpiece in order to make the nailer fire. If this mechanism is broken, dirty or set incorrectly, it can result in double fire.

I’ve seen where the contact trip gets bent from drops or impacts and doesn’t go back to a full reset between shots. This partial reset may cause additional firings.

Troubleshooting Guide

We shall do this in a systematic way. I advise my apprentices always: proceed gradually by small steps. The fix is often quite a simple thing.

Step 1: Battery and Power Check

Time Required: 2 minutes

Start here every time. Take out your old battery and look at it to see whether it is damaged or corroded. Wipe the battery contacts with a dry cloth (as necessary). Load a full charged battery and test fire in scrap material.

In case you cease firing twice, it was your first battery which did it. This does not always imply that the battery is dead, it may simply require that it be recalibrated or replaced.

Step 2: Nail Checkup and Nail Repairs

Time Required: 5 minutes

Take the nail strip off, closely inspect it. Look for:

• Bent or damaged nails
• Incorrect nail size
• Debris in the nail collation
• Rust or corrosion

Insert a new strip of the proper nails, and have another trial. Ensure that you are following the loading procedure as required in your manual.

Step 3: Setting Depth Adjustment

Time Required: 3 minutes

You need to put your depth lever back to the mid position (around 3 or 4). Fire test into scrap material which is a match of your actual project. This will take small steps until you have the right nail depth without over-driving.

Record your best settings of various materials. I also maintain a little notebook into which I write depth settings of many applications- it helps in saving time in future projects.

Step 4: Call Trip And Nose Inspection

Time Required: 10 minutes

Test the contact trip mechanism on your nose of your nailer. When set free it must spring up to its extended position in a free condition. Blast out this area with compressed air.

Look at the nose opening to see whether it has bent metal or broken. Operation sometimes can be impaired by damage that is barely noticeable.

Step 5: Internal Cleaning

Time Required: 15 minutes

Caution: Before internal cleaning, disconnect battery and complete all the safety measures.

Get rid of the magazine and other available covers. Blow dust and dirt off area of firing mechanism with compressed air. The firing pin channel and trigger valve area should be of particular concern.

When dealing with hard to remove debris, a small brush or even a cotton swab with a small drop of the correct lubricant should be used. Do not over-lubricate, this will bring more dirt.

Step 6: Test of Trigger and Safety Mechanism

Time Required: 5 minutes

Check the safety of your nailer:

• Single sequential firing (assuming this mode is in your model)
• Contact trip engagement
• Trigger response

The trigger should have a clean and consistent feel. Any softness, adhesion, or irregular reaction indicate internal problems which can be repaired by a professional.

Brand Specific Troubleshooting Tips

DeWalt Cordless Nailers

There are some distinctive features of DeWalt nailers, especially DCN. Your deWalt nail gun may not fire due to the following reasons. The most frequent ones are a dead battery, trapped nails, broken trigger or a damaged air compressor (in pneumatic models).

Common Issues:

Battery sensitivity: These tools are especially sensitive to low battery voltage.

Nail jam indicator: You should watch the LED indicators–they will frequently give you a precise idea what is wrong.

Depth adjustment: The depth adjustment is tool-free and is convenient but is prone to accidental motion.

DeWalt-Specific Tips:

• Best performance with true Dew 20V MAX batteries.
• You have the LED diagnostic system–learn the meaning of each pattern.
• Always keep battery contacts clean; DeWalt tools appear to be more particular of dirty contacts.

Milwaukee M18 FUEL Nailers

The M18 FUEL line in Milwaukee provides brushless motors and sophisticated electronics, and as such tends to be fairly reliable although it can offer some distinct troubleshooting cases.

Common Issues:

• Nitrogen spring system: They are presumably sealed tight enough not to leak during the warranty life of the tool, but I wonder how much it would cost to repair once they do leak after warranty.
• Recalibration of electronic depth adjustment is sometimes required.
• REDLITHIUM battery compatibility is essential in order to operate correctly.

Milwaukee-Specific Tips:

• The nitrogen spring system does not need much maintenance, except that it needs professional service in case of failure.
• When using REDLITHIUM batteries, optimum results are achieved.
• The electronic depth adjustment is resettable by pressing certain button combinations (see your manual).

Metabo HPT (Previously known as Hitachi) Nailers

Metabo HPT nailers are considered to be very reliable and simple in design. They are not as likely to experience electronic problems as other competitors.

Common Issues:

• Electronic issues are not widespread when compared to simple mechanical ones.
• Occasionally magazine springs.
• The depth adjustment system is mechanical and strong.

Metabo HPT-Specific Tips:

• These equipments are responsive to routine cleaning and simple maintenance.
• The mechanical depth adjustment is hardly subject to replacement.
• The tension of the magazine in spring should be checked every now and then.

When to Call the Repair Shop

See, I am very much in favor of home troubleshooting and fixing. It is a part of respecting your tools and it is learning how to use them. However, sometimes professional service is in order.

Red Flags That are a Professional Service

Internal Damage: When you notice the presence of bent or broken metal components inside the nailer, do not try to repair them yourself. Tolerances in modern cordless nailers have been precisely engineered and inaccurate repairs are hazardous.

Electronic Control Failures: When the LED diagnostics report about errors that cannot be resolved, when the electronic systems act unpredictably with new batteries and correct nails, time to go to the doctor.

Consistent Double Firing After All Troubleshooting: Sometimes, the tool may continue to double fire even after all the above steps have been tested and there may be a mechanical or electronic problem inside the tool that will only be fixed by specific tools and parts.

Failure of Safety mechanism: The contact trip is not operating correctly, the trigger is stuck or some other safety mechanism is compromised: then discontinue using the tool and professional assistance should be sought.

Warranty Considerations

The majority of the nailers that are cordless have solid warranties. These are 3 years with DeWalt, 5 years with Milwaukee and 2 years with Metabo HPT, which usually offers 2 years. When your tool is in warranty, then use it. Don’t expect to do your own internal work, which may prove to be counter-covers.

Although you might be a master of tools, warranty service can be significantly quicker and less expensive than DIY repair once you relate the cost of parts and how much time you have invested.

Cost/ Replacement Analysis

It is a harsh reality: There are occasions when repair is not cost effective. In a situation where your nailer is old and the repair bill is almost 60-70 percent of the cost to buy a new one, upgrade. Nailer efficiency and battery technology are also advancing and a new tool could benefit you in the long run.

But when you possess a good tool that is few years old, repair can make a sense generally. Properly taken care of, good cordless nailers should give many years of good service.

Prevention and Maintenance

Preventive maintenance is the best way of avoiding the problem of double firing. I understand, I understand–it is not the most interesting thing about owning tools. Yet regular treatment will save you time and aggravation in the future.

Daily Maintenance

After every use, particularly in dusty rooms:

• Spray off the magazine and nose using compressed air.
• Wipe down the exterior
• Ensure that the contact trip is free.
• Take out battery and store when you are not using it after a few days.

Weekly Maintenance

For regular users:

• Wipe out nose and magazine.
• Check all the adjustments and settings
• Check nails for damage prior to loading
• Check battery charge level/condition

Monthly Maintenance

• Full dismantling and cleaning of parts available.
• Lubricate moving parts as per the manufacturer’s specifications
• Check firing pin & driver for wear
• Check all safety mechanisms

Seasonal Maintenance

• Full working service when you are a heavy user of the tool.
• All components deep cleaned.
• Replacement of worn parts

Battery capacity testing and changing in case necessary.

Frequently Asked Questions

Q: What is it that only doubles fire in my cordless nailer?

A: Intermittent doubling of fires is typically a sign of a problem that is caused by certain conditions- usually battery charge level or nail type or depth settings. The most frequent cause is a battery with a diminishing capacity which has yet to be fully exhausted.

Q: Is it possible to change my nailer to a bump fire into a sequential fire to avoid the possibility of double firing?

A: You have the option sequential fire trigger that can easily resolve the double nailing issue. Unless your unit was supplied with it, call the manufacturer and they will send one right out. Trigger conversion kits are available in many manufactures, but do not apply to all models.

Q: Is double firing dangerous?

A: Yes, it can be. Firing twice wastes nails, may cause damage to your piece of work and in some cases may cause the nails to end up going off in the wrong direction. Safety equipment should always be used and the tool should not be used when it continues to double fire.

Q: What is the average cost of having professional nailer repair?

A: Basic service and cleaning typically costs between 50-100. More complicated repairs that involve internal parts cost between 100-200 dollars. Always obtain a quote prior to authorising work and compare this to replacement cost.

Q: Does wearing non-brand nails lead to the possibility of double firing?

A: Absolutely. Most after market nails are okay, but some result in feeding problems, resulting in doubled firing. At all times, install the manufacturer recommended nails during troubleshooting.

Troubleshooting Quick Reference Table

Final Thoughts

Double firing in cordless nailers is annoying, but it is often repairable. Most of the time, it is simple maintenance and consumption of the appropriate consumables. Begin with the easy things–battery, nails, and settings–and then go to complex troubleshooting.

I’ve been using these tools long enough to know that they want to work properly. When they don’t, there’s typically an explanation that, once discovered, makes sense. Stay patient, work methodically and don’t shy away from reaching out for professional assistance when necessary.

Remember, these are investments in your craft. Treat them with care, maintain them and they’ll do you well for years to come. And when something does go wrong? Well, now you know where to begin looking.

Always keep your tools sharp, your batteries charged and your workmanship honest. The rest will be self-explanatory.