The insert (for lack of a more technical term) is likely missing, but it would/should have held four weapons vertically, and was padded, with a tightening device to hold them securely - just like the various 'Pachmayr' cases - while the tray would hold the various things a competitive pistol shooter might need - carbide lamp, pencil, scorebook, screwdrivers, magazines, cleaning tools, et al.
If the last owner wasn't a shooter, then removing the insert would give a nice storage box.
If the last owner wasn't a shooter, then removing the insert would give a nice storage box.
