I got one for $90 shipped...so not a bad price, but had to remove some weld slag on the inside toward the top...I've taken mine apart completely and the problem that I see, that could be or is an issue, is at the front top(feed side) where they riveted on a steel plate that has two integrated feed ramps. To help assist the follower past where the bottom of the plate is, they formed a ramp into the magazine body. This ramp is a little shallow and there is a big enough gap between the mag body ramp and the bottom of the riveted steel feed plate, at least on mine it is, that this allows the follower to hang up in that area if the follower is forward as it moves upward. What I did to the follower, and what I told Surefire they should do, is to either mold a taper into the follower at the front so this will not happen at a tilt condition that the follower would not see, deepen/widen the follower channel that clears the rivets and or to put a bevel on the bottom end of the feed plate that they have riveted in front. They could also adjust that formed ramp section in the mag body, but then they could over do it and have...I guess, a less severe problem of the bullet tips/follower hitting on the way down when loading, but which is better than on the way up. This would be pricey fixing the main molds though. I think the cheapest first thing would be to stamp the feed plate with a bevel in it at the bottom. This would, if they bevel it right, guaranty that the follower with its sharp front edge, would never get hung up in that area under normal follower tilt conditions.
Notice the problem in the video when shooting the Bushmaster. It was in the area where the follower moves across the riveted feed plate. This starts to happen (the bottom of feed plate) right at about round number 7. There are 3 rivets that still need to be cleared on the way to the top and most likely the cause of that malfunction.