Wow, loads of replies! Thanks to all for input.
Shells were not reloaded. We mostly use our local brand by name of "Shaheen". The other brand used that day was S&B (Czech) Lord No. 4. Both are 67.5 mm.
Though I do not have gauge for this, will measure wall thickness today (by vernier calipers).
@Marrakai
I agree that there may be many such repairs & barrels honed.
Rust visible in some areas is fresh, as it was drizzling that day, gun was wet & dirty and not cleaned when photos taken.
That gun can easily be repaired in four words: MASTER GUNSMITH ED LANDERS
Forgive my ignorance but I didn't get it.

@Thurston
Will post exact load soon, but spent shells cannot be found as that place is about 250 miles away.
@Jerry
It may look so in the photos but there is no pitting & rust in barrels. As I already mentioned that gun was not cleaned and some surface rust due to rain.
@Geno
I used this gun once or twice after purchase and thanks God, it did not blow up, although many shots fired. Could you please elaborate, for my education, that how it could be judged that it was honed in wrong way?
Almost all replies indicate that there was an obstruction. Now my questions is that what chances a modern, in-proof, un-honed, un-repaired and well kept gun has against a blow like that, in comparison to a near junker.

@John Mann
My mention of "fluid" steel was not in any case an argument that it is strong or weak. But just to tell the specifications of gun before someone may ask that whether it is damascus or fluid.
@KY Jon
Very well said.