Well I hate to tell you we call it a breech block here at my work. When we had orange ones, we now use black ones, we use to call them Cheetos and management strongly disliked it.
So what I got from the armor and the training department is that, because of how we do turn over here to the next shift, when it rained the rifles wouldn’t get wiped down and a coating of oil. So the water apparently went into chamber area because of the breech block causing pitting in the chamber.
:: We are replacing X amount of rifles since we got new thermals. And I agree with you that nuke plants are critical and that we need to replace our rifle. As soon as it was identified our management made effort to weed out the trouble rifles and bought replacement when we ran out of replacement barrels. We are also looking to change our SOP in the hopes of preventing it::