Possible Clues:

• A colt might be in one such
• Leather case in rambling hostelry, not closed
• When others panic and looting starts inside, a case for the pistol
• The carrier belted by a gunman
• It's worn with one's arm inside
• Pistol sheath
• Receptacle for a hand-gun
• Item on a gunslinger's hip
• House surgeon has neglected one case
• A packed case