Sig MPX Review

The SIG Sauer MPX was created to replace the Heckler & Koch MP5. SIG decided to overthrow the HK MP5 sub-gun industry for many years. They had to create a gun that was easier to control, more affordable, and overall better than the MP5. I think they did a good job in some respects. These improvements will be covered in our Sig MPX Review.
My SIG MPX review will cover both what SIG has done well with the MPX as well as what it did wrong. Although they have done a lot of things very well with the gun, it is far from perfect.
Table of contentsWhat is the appeal of the gun?Ergonomics SafetyPistol gripMag ReleasesMagazine WellBolt Release/Hold-OpenCharging handleHandguardTriggerSIG MPX Review BraceSIG MPX Accessories Optics Sig MPX ReviewIronsLightsControl Devices Sig MPX ReviewSlingShooting ExperienceFinal Conclusions Sig MPX ReviewProsCons
What is the appeal to the gun?
The SIG MPX is very similar to an AR-15. All controls and features work extremely well. It’s a beautiful gun if you’re familiar with the AR-15 platform. The SIG MPX is a great choice for those who love tactical firearms or movie guns. Although I am aware of the fact that it was a major factor in my purchase, it has been one of my favorite guns.
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Ergonomics
Safety
The safety on SIG MPX is ambidextrous, and is basically an AR-15-like. The safety lever on the right side is slightly shorter, so it doesn’t rub your knuckle when you remove and put on the safety. The lever is still long enough to allow me to use my trigger finger to reengage the safety, rather than the thumb as you would with a standard mil-spec AR-15.
Overall, SIG did an excellent job designing this firearm. It’s exactly what you would expect from a gun this price. It could be improved a bit if it was closer to a Radian safety, but it beats a mil-spec version by a long shot.
Pistol grip
The pistol grip of the SIG MPX is an AR-15-style pistol grip. It looks almost like SIG copied the Magpul MOE. They chose the same grip angle they used on the M16A2 for some reason. I think they should have used a more vertical or steeper angle. Although I would have preferred to see something that closely resembles the Magpul K, I will likely switch to that grip as soon as I find one.
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Mag Releases
This gun’s magazine release is the standard AR-15 magazine release. It can be found on the right-hand side. It’s actually ambidextrous on the left side. It is also well-placed in the same spot it would be for a left-handed user. It can be used in many configurations. You can simply insert your thumb into the magazine release to remove it from the gun. I don’t understand why you would do this when you can press the magazine release with your firing hand finger. But you have many options.
Magazine Well
The magazine well of the SIG Sauer MPX magazine is quite exceptional. It has a steep bevel inside, making it easy to load your magazines into the gun and lock them in.
Bolt Release/Hold Open
The bolt release is a bit more complicated. It has an AR-15-style, ping-pong release on the left-hand side. It does have a small lever that extends to the bottom of the release, so it can be locked back. It also has an ambi-release on the right-hand side. However, it is only a bolt release and doesn’t function as a bolt hold open.
I wish there was a bolt hold-open feature on right-hand side of gun. This would make it easier to use for right-handed shooters. This gun might be easier to use if you’re lefty than your right-handed counterparts. I tend to use the same manual of weapons that I would with an AR-15 with this gun, and I don’t use the bolt lock or ambidextrous magazine release.
Charging handle
The charging handle itself is again in the AR-15 style. It has ambidextrous arms, but it’s cheaper than a Radian or Geissele handle. It’s not as robust and you can always replace it with a Radian or Geissele. It’s not in the way so you don’t have worry about hitting anything.
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I will warn you that if you have a collapsible brace or large fingers, it is important to not drop your fingers too low as it could cause damage to the brace’s mount. This is not an issue for everyone and you can train around it by using the charging handle such as rabbit ears. This is where the technique will dictate everything. However, it is something you should be aware of.
Handguard
The gun variant you choose will determine the handguard for the SIG MPX. The eight-inch barrel variant is no longer available. I have it. The handguard for that model was quite long. I replaced it with a Lancer carbon fibre handguard. It is about the same length, feels the same ergonomically, but takes a bit longer to heat up. One of my friends has one of the Copperhead models, but that handguard is much shorter and harder to mount accessories to. We’ll discuss this in detail below.
Trigger
The trigger on the MPX acts as an AR-15 mil-spec trigger. It’s all mil-spec. This feels slightly lighter than my mil-spec AR-15s, but the reset and all other functions feel exactly the same. There is just a little bit of take-up/creep left before you hit a wall or take a roll break. You can then do a semi-authoritative restart right before the break. It’s a good trigger, but you’ll want to replace it if it’s a trigger stop.
SIG MPX Review Brace
Picatinny rail sections at the rear of SIG MPX allow you to mount a variety brace options. SIG offers its own braces, or you can mount an SB Tactical M1913-style bracket — along with the SIG MPX collapsing Brace.
The receiver has two channels where collapsing bracerails can fit in. This allows for a narrower profile. Personally, I liked this design and the collapsing bracket more than I thought. Although it makes the gun wider and more unique, it’s nice to have an easy-to-use gun that folds down without having to use a folding brace.
SIG MPX Accessories
If you want something sexy, accessories can make or break a gun. Although the SIG MPX is a very attractive gun, it looks even more stunning when properly adorned. To make this gun your dream gun, we’ll show you how to mount it. This gun could be used for a fun range gun, or it could be used to build a movie-gun clone. It doesn’t matter what speed you are, mounting the right accessories will be crucial.
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Optics Sig MPX Review
It is easy to mount optics to this gun. The rail extends from the front to rear of the receiver and accepts all Picatinny-mounted optics. I have personally set up the gun with an EOTech. The EOTech is a wide optic that can cause issues with some guns through the charging handle. However, the AR-15-style charging handle presents no problems.
Irons
Although my gun did not come with iron sights it could be mounted with AR-15 folding or flip up sights. The sight radius would be adequate, but the sight should extend to the end of your handguard. It will depend on which variant you choose. Most guns currently in shipping have a 4-inch barrel. The sights will usually extend to the barrel’s end.
An eight-inch handguard is a good choice if you intend to mount a suppressor. It will protect most of the suppressor and make the gun look even better. The gun might look a bit strange if the front sight is four inches behind the handguard.
Lights
Mounting a light on the SIG MPX can be a bit more difficult than you might think. Picatinny rail sections are available, but they can be quite restrictive, especially if you have a four-inch barrel and a four-inch guard. The eight-inch handguard opens up the possibilities. Despite this, the handguard is quite large.
I am running the gun with a Modlite attached and a ModButton attached. This is then attached to the Picatinny rail insert which is on top the Lancer handguard. It’s easy to fit my thumb on it ergonomically, but it’s not the most intuitive to use. If I shoot the gun left-handed and want the light to turn on, I must use the tail switch located at the rear of my light. The tail cap is perfect for me and my hand size, but my grip is still a little compromised. The ModButton is also an option, but it would place my arm in a very strange position.
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This gun would also be a good choice if you were able to mount something like a SureFire X300 at 12 o’clock on a Picatinny insert on the Lancer handguard.
Control Devices Sig MPX Review
The Lancer handguard has three full Picatinny and M-LOK slots. The eight-inch version makes it easy to mount an angle foregrip. Even if you have the 4-inch version, there’s still a slot and half so you can mount any control device or angle foregrip to your gun.
Personally, I really like the C-shaped, angled item on my gun. However I’ve thought about taking it off because sometimes I prefer to run the gun naked. Personally, I haven’t made a decision yet.
Sling
Mounting a sling to the MPX is not as simple as you might think. The QD cup is located at the bottom of your receiver. This makes it easier to mount a sling on the MPX. Two-point slings are my preference, and this gun doesn’t have a great spot to mount a 2-point.
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One could mount it on one of the Picatinny rail sections on the receiver. Or, I can mount it to the M-LOK slots in the handguard. I wish the Lancer handguard had MLOK slots at the 11-o’clock position so I could mount a sling. My grip is not great due to all the positions on this handguard.
Shooting Experience
You will take the gun out of your Lynx defense pack at the range and insert your first magazine. Next, pull back the charging lever and let the bolt ride home. Finally, bring the gun up to target before turning your safety off and pulling your trigger. It works just like an AR-15 but has a lot less recoil. You’ll be very happy with the results if you shoot the gun suppressed. The rotating-bolt system keeps the action closed for longer, making this gun quieter than suppressed blowbacks.
This gun is one of my favourite firearms. I love suppressing it. It’s great to shoot it unrestricted, but suppressing it takes it to another level. This is the most suppressed 9mm host available.
It’s an extremely ergonomic gun that is fun to shoot. This firearm is a great choice if you shoot a lot 9mm and have access the heavier subsonic bullets. This AR-15 training replacement is great for indoor shooting ranges that do not allow rifle-caliber ammunitions. This gun shoots beautifully.
Final Conclusions SigMPX Review
This gun offers many great options. It can be used for home defense, fun at the range, or as a truck gun. There are many options.
This gun’s biggest problem is its price. The gun retails for around $2,000 and that’s before you add accessories. My gun was used and I was able to get a great deal. These guns are expensive at $2,000 and I would not have bought one. Now that I have one, I would definitely consider purchasing one at the standard price.
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These guns are amazing, especially if you want it to be suppressed. It’s not worth the money if you don’t shoot a lot with 9mms or don’t like suppressing guns. If you shoot 9mms a lot and use suppressors, your purchase will be a success. I hope you enjoyed our Sig MPX Review.
Pros
Soft recoil impulseGreat suppressor hostModularityTapered barrel (if you’re running a direct thread, can with their thread pitch)Large aftermarketCons
WeightIt doesn’t have a 1/2×28 common pitch pitch (only an issue to some)ExpensiveAs big as an AR-15 in most formats.
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