Just experienced my first OOB on a home built Polymer80, 9mm. It did not survive! An aluminum lower would not have been damaged IMO.
This gun has been perfectly reliable until today but I decided to fire the last mag at a faster than normal pace. Surprised the crap outta me.
Probably bolt bounce from the looks of everything. Mag well split apart at the front corner and the PMag body housing the Endomag also split apart. The Endomag insert had no damage.
Was the upper cerikote or similar or blued?