I've compared the dimensions of the CMC to Meg-Car mags, which exhibit no issues. Between them, the only dimensional difference I could find is the CMC is only slightly thicker near the top of the mag, in the area just below where the follower is at rest. And by slightly, I'm meaning a couple of thousandths of an inch. The problem only occurs after the last round is chambered and the magazine is empty. When the trigger does stick, it resets freely if I move the magazine by playing with the base pad.
CMC mentions positioning the (unconventional) follower manually, prior to inserting an empty mag into a gun:
"When “bench testing” for slide lock, before inserting the magazine into the pistol, first press down on the top forward section of the follower before inserting the magazine into the pistol. This will place the follower in the same position it would be after the last round was fired out of the magazine. If the follower was seated properly when the slide is manually cycled to the rear it will engage the slide stop, locking open the slide."
Placing an empting mag into the gun, with the slide closed, I cannot get the trigger to stick. CMC mentions the Power Mag follower being designed for positive slide lock. Without stripping the pistol down, it seems the follower being dragged/tilted forward after the last round is chambered, causes the magazine tube to then be tensioned against the trigger bow. Perhaps the trigger bow is just slightly out of spec? For now, I'm just going to set that CMC mag aside. While googling this issue, it seems I'm not alone in experiencing this malfunction.
