From Wikipedia: "An air gun (e.g. air rifle or air pistol) is a rifle, pistol, or shotgun which fires projectiles by means of compressed air or other gas, in contrast to a firearm which burns a propellant. Most air guns use metallic projectiles as ammunition. Air guns that only use plastic projectiles are classified as airsoft guns."

This is based on a Daisy air rifle I've got in my closet.  It triangulates to ~750 polygons.  This was one of the more difficult pieces I've done so far.  It includes details like both front and rear sights, bolt, trigger, and safety.  No materials.  Making it into a hunting rifle should be pretty easy.