Interesting point, look at how a soda can will "weep". Then consider that powder attracts moisture.....
Right, it does make you wonder if it was not the bullets & pouches not so much the gun. The gun has done well in test after test after test... I'm not one to think GI's would outright lie, exaggerate, sure, but not many would outright lie... So let's think of what COULD cause the outcome some GI's saw... I think we might be on that track...