The magazine is standard NATO STANAG M16-type magazine. Interestingly enough the standard aluminum magazine is interchangeable. As you can imagine, there is a plethora of aftermarket M16/M4 magazines out there. But beware, they are not all compatible. During testing of the rifle, the rifle was shot successfully with Colt GI mags, Lancer AWM and Magpul Gen 2. However, the Magpul Gen 3 would not function. The front area of the magazine is what makes a difference. If there is no change in geometry from the original GI mag the mag will fit. It was also found that the HK high reliability functioned fine, but their polymer magazine would not lock into the mag well. Basically, any of the aluminum/steel magazines function perfectly. The polymer magazines were dependent on the angle of the curve on the front top of the magazines. The shape of the magazine well in the front is the location where the incompatibility of some of the polymer magazines was found.
The safety is ambidextrous and is also used for disassembly. The ARX100 of course is a semi-automatic only rifle. The trigger pull of this rifle broke at a heavy 9 ¾ pounds. During test firing the trigger proved to be heavy and, in fact, with firing numerous shots, the trigger pull became rather fatiguing to my trigger finger. It is safe to say this trigger will not fire unintentionally. There are actually three magazine release points on the rifle located in front of the trigger on both right and left side, and on the under bottom of the trigger guard. The bolt release is also ambidextrous, located in front of the trigger finger on both sides. There is a pistol grip storage compartment in the bottom of the pistol grip.
In the front of the hand guard on the right and left sides are two Mil-Std-1913 rail segments. They can be removed but the mounting bracket is present. It would not be comfortable to hold. On the bottom of the hand guard is a smooth panel that can be removed allowing for an adapter to allow a 6:00 position Mil-Std-1913 rail panel segment. Also located on the front portion of the receiver on both sides in front of the magazine well is the barrel quick release mechanism. After the bolt is locked to the rear, the lever is pulled down on each side similar to that of a Glock pistol and the barrel assembly is pulled right from the front of the receiver.
Disassembly is simple and requires no tools of any sort. Remove the magazine and ensure there is no round in the chamber. Depress the stock latch button and fold stock assy to the right. Pull down on the lower receiver while holding the safety lever in the disassembly position and depressing the retainer plate through the back of the receiver and separate the upper from the lower receivers. Pull the bolt handle back until it aligns with the marks on either side of the receiver. Pull out the bolt handle and place it in the center position towards the barrel. Pull the bolt carrier group out of the rear of the upper receiver. Pull downward on the barrel release lever from both sides and slide the barrel out of the upper receiver. To remove the bolt, rotate the bolt handle to the right or the left side and pull the bolt back through the bolt carrier, rotating it to allow the bolt cam to follow the cam path and remove it from the carrier. To remove the firing pin, press inward on the firing pin and pull the cam pin out of the bolt. The firing pin and spring will now come out of the back of the bolt.
Overall, this rifle is quite unique and shows some very out of the box thinking on behalf of Beretta. It is not perfect but nothing ever is. It is safe to say this gun is not a derivative of another manufacturer. The bolt mechanism in conjunction with the ambidextrous element of the design are really new out of the box thinking. This is defiantly one of the only completely ambidextrous assault rifles in the world. The rifle is maintaining a combat record with Italian Forces, Albanian Piece Keeping Forces, and Mexico’s Federales, Kazhakstan and the security services of Turkmenistan. The ARX is rather new to the US commercial market but bound to have its loyal Beretta followers.