LE mags often need adjustment to feed reliably. Might be a bit loose and too low to pick up rounds, lips bent, etc. Careful bending of the feed lips, etc should solve the problems. Mags aren't bad, just need some tinkering and time.
Bottom line, they weren't intended to be used as for semi autos, they were intended to stay in the rifle and be loaded with chargers, which is why the mags usually were numbered with the rifle's serial number. You'l be surprised how quick reloading with chargers is.