4 Main Mossberg 100 ATR Problems And How To Fix Them

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I’ve recently spent some good quality time out in the field with the Mossberg 100 ATR. You know, getting to know the ins and outs of this rifle. 

I’ve encountered some common Mossberg 100 ATR Problems with the Mossberg 100 ATR that you should know about. These include issues with the bolt, accuracy, the firing pin, and the trigger. Now, these aren’t deal-breakers, but they can definitely put a damper on your shooting experience. 

We’re going to delve into each of these problems and offer practical fixes. That way, you can get the most out of your Mossberg 100 ATR. So stick around; you won’t want to miss this.

Overview of Mossberg 100 ATR Issues & Solutions

Mossberg 100 ATR ProblemsSolutions
Stiff BoltClean and oil the bolt components.
Accuracy IssuesTighten scope and experiment with ammo.
Firing Pin Light StrikeClean and lightly oil the firing pin.
Trigger SlackDIY adjustment or consult a gunsmith.

Top 4 Mossberg 100 ATR Problems & Solutions

1. Problem with the Bolt

So, first up is the bolt. Man, it gave me some headaches. When you’re out in the field, the last thing you want is a bolt that’s not smooth. 

The issue I faced was that the bolt was a bit stiff, which led to some awkward moments while chambering rounds. It’s not a huge catastrophe, but a stiff bolt can really slow you down when you’re in a situation that needs quick action. 

And let’s not forget, it takes away from the overall enjoyment of using this firearm. You’re not alone if you’ve faced this; it seems to be a fairly common gripe among Mossberg 100 ATR users.


Alright, here’s what worked for me. Grab some high-quality gun oil—nothing fancy, just something reliable. 

Then, disassemble the bolt and give it a good cleaning. Be generous with the oil, especially on the moving parts. I also went the extra mile and used a nylon brush for the nooks and crannies. Put it all back together and work the bolt a few times.

 You should notice a significant improvement. In my experience, this simple maintenance routine made the bolt action much smoother. So, it’s a straightforward fix that can make a world of difference.

2. Accuracy Problem

Next on the list is the accuracy problem. It’s super frustrating when you line up a perfect shot, and then the bullet strays off course. 

Yep, I faced that, too, with the Mossberg 100 ATR. It was all set up: a stable rest, perfect sight alignment, and yet the bullet wasn’t hitting where I expected. 

This isn’t a toy; it’s a tool that should do its job when called upon. An accuracy issue is more than just annoying; it could be critical depending on your use of the rifle. Like the bolt issue, this isn’t an isolated case. I’ve heard others express similar concerns.


Here’s what worked for me. First off, check the scope. A loose or misaligned scope can throw off your aim. Tighten all the screws and make sure it’s perfectly aligned. Next, you might want to look into the ammo you use. 

Different rifles prefer different ammo, so try a few varieties to see what your Mossberg likes best. Lastly, don’t underestimate the power of a good barrel cleaning. 

Residue buildup can affect accuracy. I cleaned the barrel thoroughly and switched my ammo, and voila, the shots were much more accurate. Simple steps, but they do make a big difference.

3. Problem with the Firing Pin

Now, let’s talk about the firing pin. This is one of those components that you expect to work every single time. But with the Mossberg 100 ATR, that wasn’t always the case for me. 

I pulled the trigger a few times and heard the click, but nothing happened. Yep, a “light strike,” they call it. It’s when the firing pin doesn’t hit the primer hard enough to ignite it. 

Talk about a letdown, especially when you’re in the middle of a shooting session. It can be a real inconvenience, and, in some scenarios, it could even be dangerous. Clearly, this is something that needs addressing.


So, how did I tackle this problem? First, make sure it’s not an ammo issue; some ammo types can be more prone to light strikes. 

But if it’s consistently happening, it’s time to check that firing pin. What worked for me was a good, thorough cleaning of the firing pin and its channel. 

Remove any grit, grime, and old lubricant. Then lightly oil the firing pin; don’t overdo it, as too much can attract dirt. 

Put everything back and give it another go. For me, this resolved the light strike issue, making the firing pin hit like it should. Trust me, it’s worth the effort.

4. Trigger Problem

Last but certainly not least, let’s dig into the trigger issue. Now, a good trigger pull can make or break your shooting experience.

In the case of the Mossberg 100 ATR I tried, the trigger had way too much slack. It felt spongy, and I had to pull it a considerable distance before it finally fired. 

The inconsistency in the trigger pull was distracting and, frankly, irritating. It’s a problem that can mess with your aim and timing, which no one wants when they’re trying to get that perfect shot.


Here’s the deal on how to fix this. You’ve got a couple of options. The first is a DIY adjustment if you’re comfortable fiddling with the trigger assembly. 

Adjust the set screws to reduce slack, and test it multiple times to make sure it’s reliable. The second option, which is what I opted for, is to take it to a professional gunsmith. 

They can either adjust your existing trigger or install an aftermarket one that provides a more consistent and responsive pull. 

After getting mine tweaked by a pro, the trigger felt much better, and my shooting improved noticeably. It’s an easy fix that can make a world of difference.

Final Verdict

In wrapping up, the Mossberg 100 ATR is a solid piece of hardware. However, it does have its share of downsides—issues with the bolt, accuracy, firing pin, and trigger specifically. 

But, hey, no product is perfect. What counts is how you manage its weaknesses. My time in the field with this rifle showed me that many of these issues are surmountable with a little TLC and maybe a trip to a professional gunsmith. 

Sure, these problems can be annoying and can even affect your performance, but the good news is they’re fixable. 


How many shots does a Mossberg hold? 

The basic Model holds six shots, including one in the chamber. An extended version holds eight shots in total.

What does Mossberg ATR stand for? 

ATR stands for “all-terrain rifle.”

What is the length of pull on a Mossberg 100 ATR? 

The length of pull on this model is 13.5 inches.

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I'm Micheal, an avid shooter and hunting enthusiast from Texas. I'm a recreational shooter who loves to spend time at the range and enjoy learning about new firearms and gears. I love to write about guns and share my passion for shooting with others.

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