6 Ruger ar-556 MPR Problems You Should Know Before Buying

Ruger’s AR-556 multi-purpose rifle is well-known for its accuracy and durability, making it a popular choice for both experts and amateurs. However, this gun is not without flaws.

Some of the Ruger ar-556 mpr problems you are likely to encounter include under gassing, double feed, bolt getting stuck, failure to lock back slide, releasing multiple shots at once, and split brass.

In this essay, I’ll go through some typical Ruger Ar-556 problems and remedies.

Features & Specifications of Ruger ar-556 MPR:

StockSynthetic, Collapsible
Barrel Length18 inches
Height8 inches
Thread Pattern1/2″-28
Capacity30 rounds
Weight6.8 lb.
Ruger ar-556 MPR Problems and Solutions
Ruger ar-556 MPR

Common Ruger ar-556 MPR Problems and Solutions

Quick Overview of the Problems and Solutions

Not leaving the bolt open with an empty magUse standard GI magazine
Multiple shots at onceReplace stock trigger with CMC drop in self-contained single stage 3.5 lb pull trigger
Double feedLubricate the rifle/Replace the extractor/ send to Ruger
Failure to lock back slideTrying changing gas block screw/buffer spring
Under gasInstall adjustable gas block or change the gas tube / install lightweight bolt carrier group or spring

1. Not Leaving the Bolt Open with the Empty Mag

Once you have fired the last round, the ideal response one would expect from a rifle is to keep its bolt open. But, the Ruger AR556 sometimes does not keep the bolt open.

Possible Reasons:

The problem appears when the empty magazine cannot push up the bolt catcher. The bolt catcher is the device that holds the bolt once the magazine is empty.

But some magazines, especially the stock magazines often fail to push up the bolt catcher.

If the recoil spring is too stiff it can push the bolt before the catcher is up it.

The Fix:

All you have to do is to switch over to a different magazine.

The stock magazine that comes with the package is often at fault. There have been many complaints that they cannot keep the bolt catcher up to hold the bolt.

Using a standard GI magazine would solve this problem. You could also try other variants if you fancy. But, make sure they can keep the bolt catcher open when it is empty.

2. Multiple Shots at Once

There have been claims that the rifle shot two or three burst shots on a single trigger squeeze. This problem could cause an accident as you will start shooting burst shots out of nowhere.

Possible Reasons:

It occurs when one of the trigger groups holding pins falls out and the trigger mechanism in the lower receiver becomes canted laterally.

It could be something binding the disconnector or a faulty spring that does not properly push the disconnector up.

Installing the hammer wrong could also cause this problem.

The Fix:

In a nutshell, the basic trigger group on this particular new Ruger 556 rifle has insufficient detents to keep the trigger group retaining pins in place.

The best course of action is to swap the stock trigger for a CMC drop-in, single-stage, 3.5-lb pull the trigger, in case the problem lies with the trigger component.

Otherwise check if the hammer is installed properly.

3. Double Feed

When two rounds attempt to feed into a semi-automatic at the same time, it is known as a double feed.

Possible Reasons:

The slide is partially in the rear when the gun locks up since there isn’t enough clearance for both. It cannot be fired once more until the issue is resolved.

If you face this problem frequently then there could several reasons involved like low maintenance, internal flaw, faulty extractor, etc.

In case the magazine is faulty, then it could also cause the problem. Magazines with strong spring tend to push the bullets with more power.

If the recoil spring and magazine spring does not sync, it can cause the issue.

The Fix:

In an AR556, double feeding is typically an OE or mag problem. A well-oiled bolt may solve the majority of cycling problems with a new AR. The extractor might be replaced to address your issue.

But before you take any action, try placing one bullet in the magazine to test the ejection. If ejection works as it should, you should then check the magazine spring and the recoil spring if they are in sync.

4. Failure to Lock Back Slide

This problem was admitted by Ruger’s customer care, which is a move that most companies would not make. They also mentioned recent models suffering from this problem.

Possible Reasons:

In previous models, the gas block screws were becoming loose and shortening the bolt’s stroke. This is the reason those models often experienced failure to lock back slide.

It could be a bolt stop problem, as it should engage the rear of the mag follower and prevent the bolt from moving forward, but it could be stuck or rounded off.

The Fix:

The best way to avoid this problem is to not buy the old Ruger AR-556 models. If for some reason you do and face this problem then you could do two things.

As the gas block screw getting short causes this problem, replacing the screw once it wears out would solve the problem. Also, you install a stronger buffer spring.

5. Under Gas:

If your rifle is gassed you will notice how it ejects the casing. The under-gassed rifle will barely eject the shell. It can also cause failure to eject.

Possible Reasons:

There could be fault with the barrel and the gas tube. If you are facing this problem, it is most likely to be one-off problem.

Another cause of this issue could be the heavy bolt carrier group. If the BCG is heavy then the generated gas cannot operate to the full extent with its limited energy.

As the gas pressure also depends on the ammo, if the ammo fails to generate enough power it can also cause the problem.

The Fix:

If you notice your rifle is under-gassed, then installing an adjustable gas block would most likely solve the issue.

Another option for you is to replace the current bolt carrier group with a lighter alternative. Because the generated gas will be able to perform better with the light bolt carrier group.

User Feedback on Ruger ar-556 MPR Problems

Ruger AR-556 has received fantastic reviews from the community since its arrival. Discussions on ar15 and glocktalk are a testament to it. It is a great gun with very few shortcomings.

The Ruger AR-556’s trigger appears to be its weakest point. Instead of the typical 5-6 pounds, it weighs roughly 8-9 pounds and is substantial. However, you may easily change the trigger.

The Ruger AR-556 is a dependable, accurate, and easy-to-use rifle with little recoil. Ruger regularly manufactures high-quality weapons at reasonable costs, and the AR-556 is no exception.

If you’re searching for a simple, uncomplicated semi-automatic rifle that can fire straight, the AR-556 is unquestionably a must-have.

In case you’ve been thinking about purchasing an AR but haven’t made a decision yet, there is no reason not to do so. Therefore, you can’t go wrong with this wonderful weapon.

Top 3 Alternative Guns of Ruger ar-556


It has a free-floating, cold-hammer-forged MIL-SPEC barrel with a chrome-lined bore and chamber. Operating controls that are completely ambidextrous where left handed people will have problem with ruger ar556.

HK SL8-6:

The SL8-6 is set up for a 10-round single-stack unit. The semi-automatic SL8-6 has a larger barrel and its own bolt system to feed from its magazine. It is constructed almost entirely of a reinforced carbon fiber polymer, which makes it more rugged than ruger ar556.

Zastava ZPAPM90PS:

The completely chrome-lined 18.25-inch barrel of the Zastava Arms M90 comes with an adjustable gas system right out of the box.

Frequently Asked Questions (FAQs)

Is the Ruger AR-556 MPR a good gun?

The Ruger had outstanding accuracy, with some rounds printing less than one MOA.

What is a Ruger AR-556 MPR?

The Ruger AR-556 MPR is a Semi-Auto Rifle that has a direct-impingement and rifle-length gas system.

What does MPR stand for Ruger?

MPR is an abbreviation for Multi-Purpose Rifle. It is a direct-impingement rifle with more capabilities than a standard, entry-level, 16″-barreled carbine.

What ammo does Ruger AR-556 use?

The Ruger AR-556 can handle the more typical since it features a 5.56 NATO chamber. ammunition for the 223 Remington and the somewhat hotter 5.56 NATO cartridge.

Is the Ruger AR-556 barrel chrome lined?

The barrel is not chrome lined; it is constructed of Chromoly steel. The Ruger flash suppressor is placed on top of the threaded barrel.


Ruger AR-556 MPR is an excellent entry-level rifle for the AR platform. It may not be the most expensive rifle on the market, but it has all of the features you’d expect from a contemporary AR-15 and is reasonably priced.

All the Ruger ar-556 mpr problems we have explained above and provide you the satisfactory solutions.

The gun is accurate, dependable, and well-handled, and you do not need to acquire accessories for the rifle because it comes already equipped.

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