I feel sure that the case started life looking similar this originally for a double side by side.

[Linked Image from i.imgur.com]

The lay out seems to be a little askew with things being in the wrong place, the cleaning rod turn buckle is there but doing what? Also the divider's seem to be a mishmash of divider thicknesses with what looks like the stock compartment and the extreme left compartment have clumsy strips to hold compartment covers. Finally it looks as if stops have been attached to the case lid to hold the barrel stopping it from rattling, a correctly fitted case would have the spacers below the barrel and the case lit would hold it secure. All in all I think it has been a amature re line and fit but they lost their way.

The only lessons in my life I truly did learn from where the ones I paid for!