Factory Ruger Mark Pistol Case.
This is the case that a 5.5″ and under Mark IV ships in.
They were removed from parted out Pistols.

Lot of space in the compartment and also a lot BELOW the molded insert

Inside dimensions (usable) approx. 7″ x 11.5″ x 3″
Outside dimensions approx. 10″ x 12.25″ x 3.5″

LAST TWO PICTURES
Are concept pics,, NOT INCLUDED
Just showing what can be done with some foam