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With the Herrington Arms +5 SIG P320 magazine extension, there is no need to fear running dry in any situation where every shot counts. It works perfectly with 15,17, and 21 round magazines! This mag extension on a 17rd mag fits in the 141.25mm USPSA gauge!
This highly durable mag extension is made of light yet very strong weapon grade 6061 aluminum. It works well in all weather conditions and won’t break easily, even if dropped with a full magazine. THIS MAG EXTENSION DOES NOT FIT THE X5 LEGION OR AXG MAGWELLS FROM SIG SAUER! 
This mag extension has been precision engineered on state-of-the-art CNC machinery to consistently deliver the same outstanding quality, time after time-every time. This extension was also designed to work perfectly with the Icarus Precision Sig P320 grip modules, including the SOCOM grip module! It is available in FDE Cerakote and matte black anodized finish, and will add a touch of extra class to your P320 pistol.
Key Highlights of the P320 +5 Magazine Extension
Your +5 Mag extension gives you that extra edge when you really need every round
The Flat Dark Earth Cerakote or full matte black anodized finish variants create an eye-catching contrast with your EDC weapon
The weapon grade 6061 aluminum provides a very light yet extremely durable product
It can take a lot of abuse and can be used extensively in IDPA-style competitive matches
This product comes with a lifetime warranty. No questions asked!
It can be installed without the help of a gunsmith
The complete package includes an Allen bottom plate, key, set screw, pin, and extension body[1]
The SIG P320 Pistol
The Sig Sauer P320 (chambered in 9x19 Luger) is an ideal EDC weapon. It can be concealed easily and is also a great choice for an open-carry weapon. From your duty holster to a backpack gun for trekking in the woods, this versatile pistol does it all.  
Like all other SIG handguns, the P320 is a reliable and durable handgun. This weapon carries SIG’s legendary reputation very well indeed. In fact, its M17 and M18 variants are now the official side arms of the US armed forces. Our brave men and women in uniform carry these guns in hotspots all over the world with total confidence.
The Herrington Arms Sig P320 +5 Magazine Extension
There are many times when your pistol’s standard mag capacity might not be enough for the job at hand. Here, a mag extension can be very useful since it will allow you to continue your trigger time without swapping your magazine. You can use these extra rounds to practice your speed shooting drills, participate in a practical shooting tournament, or even use them in a self-defense situation.
Whatever the application, your +5 mag extension would always be up to the task, and provide you that extra firepower – just when you need it the most.
Product Specifications
Finish: Black Anodized or FDE Cerakote
Material: 6061 Aluminum
Compatibility: Sig P320, Icarus frame
Capacity: +5
There is no such thing as too much ammo. If you carry a weapon, you should always make sure that it's fully loaded and topped up with a few extra rounds. You never know when you might need them!
[1] Magazine is not included in the package


Every compensator we manufacture has undergone rigorous reliability testing!

The design phase

Every product we make goes through a week long design process and multiple versions before we machine a prototype!

CNC Machining

We currently machine all of our compensators on 2 brand new Doosan DNM4500S CNC milling machines and a 2019 Tormach 1000mx CNC milling machine!


The answer is easy! All you need to do is purchase the threaded barrel that matches your slide. For example, if you have a carry length slide you need a carry length threaded barrel (4.6"). If you have an X compact slide you need a X compact threaded barrel (4.3"). This will allow you to run a longer frame and give you an integrated look.


Yes they do. We have run tens of thousand of rounds through all of our models and have had zero malfunctions. If you are having an issue with a build, it is likely the case you have installed our prodcut incoretly or your handgun needs broken in. Compensators need a smooth running system to be reliable. A new handgun has tolerances that need to be worn in before we suggest adding a compensator

-It's easy! We designed our comps to be self-timing so all you have to do is

- Remove your slide from you frame

- Remove your guide rod assembly

- Apply Loctite to barrel threads

- Thread comp onto barrel until it stops

- Back off a 1/8 turn

- Apply Loctite to set screws

- Tighten down set screws


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Marcos A.
United States United States

Mag extension

Product looks and feels great. Definitely going to put them through the ringer to see how durable they are but they fit my mags good and functions well.


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