The two guns that I know blown up were factory and used factory ammo. One WAS a Browning GTI with Win AA handicap load and the other a Mossberg pump with Federal ammo In the Browning case , Winchester took the blame and in the Mossburg, my friend just threw is away after no resolution I overloaded one time--loaded 48 gr 7625 (double load) in a federal Paper case , bad recoil in my SidexSide
but no lasting damage.