As promised we took the 15 round G48 mag from Shield Arms our for a test run. We fired 5 mags through the gun with 115 FMJ rounds loaded to 15 round capacity. 3 out fo 5 times it did not lock back on the last round, and the after the 3rd mag, it would no longer lock back at all. I wanted this mag to run clean because I want the same set up Joe has. We suspect a weak spring or something else is causing the follower to seat high enough to catch the slide.
Visually, we can see the follower not coming back up high enough. Instead of trying to shade tree mechanic and giving you guys a half assed explanation, Joe decided to report the problem and see what kind of warranty and customer service he will get from Shield Arms. The rounds fed perfectly otherwise. It may just be this one mag. This is also a first run item. I usually stay away from generation 1 of anything to let the bugs get worked out. We’ll update you when Joe hears back from Shield Arms.