Some trouble to report on the humungo-mag. First set of 31 bullets that went through it were great; no missfeeds or loading trouble. But the second time I used it, the bullets started catching in the magazine and nosing down, locking the action back as though the mag was empty. This happened at least three times and required that I remove the mag, snap the stuck round back into alignment, then replace the mag and close the breach again.
Maybe it needs more lubrication. Either way, it's a funny visual gag, but I wouldn't trust it in an actual live-fire situation.