A friend took his new shield 9 to the range last night and on the second round it locked open. we removed the mag and had to work like hell to get the slide to close. Tried different mags and shooters the problem continued. We field stripped it and didnt see anything obvious.

So its going back to the factory, but he is quite down about it. Between the guys at the range last light 3 other guys have shields that have been great, so we tried to reassure him it will work out fine and he will love the pistol when returned.

Any clue what the problem could be?