Odd WWII 4inch Barrel question

I think that this is the work of a amature gunsmith.

Instead of obtaining the proper tool to remove the barrel,

this person simply chucked the barrel assembly over the chamber and removed the pressure by cutting off the shoulder to where the barrel could be removed by hand.

No reason to accuratly center it as it was to be junked.

There in no explanation for acts of ignorance !!!

They just happens !!!

ViggoG