SIG Introduces P320 30-round magazines Extendos for All

The SIG P320 has been slowly and steadily eating Glock’s lunch. The P320 was SIG’s first polymer frame, striker-fired gun, and it’s grown into quite the pistol. After the Army adopted the weapon, the rest of the military followed, cementing the weapon in the consciousness of the gun-buying public. SIG and the aftermarket also haven’t been afraid to greet the SIG P320 with open arms, allowing for development and customization to an extreme degree. SIG’s latest release is that of an OEM 30-round magazine. The P320 30-round magazines have taken the platform a step further. 

Plenty of companies have produced extended P320 magazines to varying degrees of success. ETS produces some polymer frame models, and while they work, they aren’t perfect. They only work with polymer-frame P320 pistols and don’t work in PCCs or metal-framed P320s. Promag makes some, but Promag…. Now that SIG is producing a P320 30-round magazine, we have an option for the standard pistols, as well as the variety of rifles and braced pistols that have made their way to the market. 

Breaking Down the P320 30-Round Magazines

The P320 30-round magazines take a cue from the P365, believe it or not. The P365 15-round magazines come with this grip extension that is heavily checkered but also removable for use in the P365XL. The P320 30-round magazines come with a polymer wrap-around base plate. You can remove it and replace it with a standard base plate if it’s not your style. 

On top of that, the insert is textured with a very grippy material. The pads of texturing run up both sides and that coordinate exactly where your thumb and forefinger fall when you draw your magazine for reloading. It’s more than a long piece of bare metal. The polymer inserts fit perfectly in a full-sized handgun grip or a PCC magwell. 

The followers are bright orange and easy to see. This is especially true through the witness holes that allow you to keep watch on your ammo count. Speaking of witness holes, SIG ditched the witness hole for every round, and it’s a wise move. Seeing as how these will very likely be used in PCCs, those witness holes could be an issue. They allow for the ingress of dirt and debris into the magazine. If we had thirty of them, we would have thirty points of ingress. 

Instead, the P320 30-round magazines feature only six witness holes, one every five rounds. It allows for a very educated guess in terms of ammo capacity while protecting the inside of the magazine and its overall reliability. 

Why It’s a Big Deal?

The P320 30-round magazines allow the SIG P320 and its magazine platform to move forward. I own a Banshee Mk17, and it’s a mighty fine weapon, but the magazines topped out at 21 rounds. It’s been a bit frustrating. Now we have an OEM option that embraces the standard capacity for modern semi-auto rifles and braced pistols. 

A good bit of Glock’s success isn’t due to Glock. It’s because they made their magazines in various capacities for various calibers. Those magazines have been embraced by rifle and braced pistol platforms. SIG finally realized that the American gun owner loves extendos and P320 owners wanted more. 

It’s a good sign that we now have a quality, reliable, extended magazine that works in my P320, my Banshee, and my metal-framed P320 model. The one downside is the MSRP of 60 bucks…if you can move past that, your P320 now has a man-sized magazine option. 

Travis Pike
Travis Pike is a former Marine Machine gunner who served with 2nd Bn 2nd Marines for 5 years. He deployed in 2009 to Afghanistan and again in 2011 with the 22nd MEU(SOC) during a record setting 11 months at sea. He’s trained with the Romanian Army, the Spanish Marines, the Emirate Marines and the Afghan National Army. He serves as an NRA certified pistol instructor and teaches concealed carry classes.