No offence, Saad, but if that brutally peened front lump in the last photo is as bad as it looks, it's a pretty clear indication that the gun has been 'restored' by an ignorant vandal of a gunsmith at some stage in the past. Who knows what else he did, including striking the barrels beyond proof, honing the bores without raising dents first, etc. What is the barrel wall thickness at the burst?
Having said that, it certainly looks like an obstruction to me. As pointed out by 2-piper, the characteristic bulging prior to fracture is certainly in evidence.
