I saw a guy at an mg shoot monkeying around with the receiver and barrel and when he engage the receiver stud into the shroud...out popped this bushing from the end of the barrel shroud hole for the receiver stud.
The guy just dusted it off and slid it back into the forward end of the barrel shroud hole that accepts the receiver stud (the stud with the interrupted threads that engages the shroud). This bushing was maybe 3/4 of an inch long and had a little half oval notch cut-out in it. The guy said it just is a light press fit and it comes out sometimes.
I assume it supports the forward end of the receiver stud so you can get an easy engagement into the receiver lockup after a barrel change.
Shouldn't a part like this be pinned or something instead of a slip fit? It doesn't sound right to be dropping out parts and the rest of the mg seemed very well thought out. Was it designed for a heavier press fit you think?
That thing looked nice otherwise.