I don't pretend to know much about FA firearms, but this one has me stumped.
I saw a gentleman shooting what looked like a FA MAC 10, but to my surprise all I found was 45acp shells under the table. So my first question is...what is it?
Second question, why would it bulge the brass like this?
I had little trouble resizing it back to shape, but curious why it bulged so far up the case. The thing was really fast, like an UZI.