Defective ammo was a huge problem. Large lots of ammo was destroyed for how bad the ammo was.
The whole reason they decided to replace low number receivers in rebuild, was because of how they might respond to defective ammo.
Now one thing never covered in the books was how barrels also could respond negatively to defective ammo and burst. This is on high numbers as well.
There were more barrels that burst than there ever was receivers that failed. In fact in 1927 they had stated they had so many barrels fail, they redesigned the ramp of the barrel to give added support to the cartridge case.