The P320 Mag X AR Adapter
The SIG P320 is on the road to being one of the most successful handguns introduced since the Glock Safe Action Pistols. The P320 has been beating Glock left and right it seems with numerous police forces, and of course the United States Military has adopted the M17 and M18 variants of the P320. SIG is tossing a ton of support behind the gun and producing tons of different models designed for duty, concealed carry, and competition. Running handgun mags in a rifle has always been a popular option, and if you own a P320 you may want to do the same. The Mag X from Matador Arms is one way to make it happen.
The Mag X adapter is designed to fit in a mil spec magazine well on your average AR 15 lower receiver. This allows you to use the vast majority of AR lowers. However, they must be multi cal Mil-spec units. The Mag X may not fit some oddball lowers like the Polymer 80 lowers floating around.
The Mag X adapter fits into the magazine well and is secured in place by the magazine release button. To prevent the Mag X from falling out at the wrong time a set screw allows you to secure it in place and this prevents it from being removed. The screw sets in over the top of the Mag X adapter and is only accessible with the upper and lower separated.
Putting the Mag X in Action
Installation takes no time at all. It slides in like a magazine then all you need to do is set the screw. That's it.
The Mag X uses a paddle style release built into the adapter to provide an ambidextrous magazine release. It's actually easy to use, but takes some retraining when you have an AR in your hands. It's so easy to just hit that standard mag release and then blank when nothing happens. Admittedly my own muscle memory of the AR platform took over and I'd hit the wrong release to reload quite a few times.
If you've trained and used the platform a lot you may have some issues and have to slow it down a bit to get better at it. The good news is the magazine release is easy to reach and intuively designed. It's placed in front of the magazine and as you press it in it releases the magazine. The design allows you to grip the magazine and press the release at the same time in one fluid motion.
This allows you to remove the magazine if it doesn't drop free, and of course allows you to retain the magazine when you commit to the reload.
Speaking of Reloads
Reloading is easy because the magazine well is essentially a funnel. Visiually when you attempt to reload its odd, the mag well looks huge but in reality it is the size of pistol mag. It's a little tricky, but doable. I used the X5 model 21 round magazines and they are quick and easy to reload. Plus it adds a few extra rounds to the gun.
The Mag X works with Glock or hybrid bcgs, but will not work with Colt SMG bolts. It works reliably as well. It was slightly stiff when I started, but it ran. Downloading the magazines by one round made things a little smoother, as did loading it with the bolt locked to the rear. Regardless of how I used and loaded the weapon the gun ran and the system worked perfectly.
The Mag X from Matador Arms is an excellent piece of gear. It allows you to run P320 magazines through a standard lower and an appropriate upper receiver. The adapter holds the magazines perfectly in place for reliable and smooth feeding. The Mag X is easy to install, and to remove and is made from carefully machined aluminum. It is ergonomic by design and simple to reload once you get passed your AR muscle memory controls.
Mag X has created an excellent piece of kit that allows you make your own P320 mag takin' AR. It's well designed, and well made. The design is simple and allows you to make a 9mm AR with lowers you can find anywhere, or maybe one you already have. Check out Matador Arms here.
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.