I have a number of stripped LRB AR15 upper receivers. All the ejection port covers (2 sources - RRA & Brownells) I have tried will not close without manually depressing the detent. The receivers seem to have a notch that is actually too deep to depress the detent when closing. The detent retaining pin is installed in a 'blind' hole - that has stymied my thoughts for an easy fix.
Has anybody had this issue and come up with a solution? An email to LRB about this issue has gone unanswered.