Fired at the muzzle, a representative .44 Magnum load (15.6 g, SP, 400 m/s) reaches roughly 27 mm (1.1 inches) into polycarbonate. That is enough to defeat a typical barrier of this material — treat anything behind it as exposed.
About Polycarbonate
A polycarbonate pane (~12 mm); true bullet-resistant glass is far thicker and layered.