Complex sentence: His personal sidearm is usually a customized and/or expensive.45 caliber pistol: in "Still Life with Crows", it is a Les Baer.45 caliber government model.
Split into simpler sentences: His personal sidearm is usually a.45 caliber pistol that is expensive, customized, or both. In "Still Life with Crows", it is a Les Baer.45 caliber government model.