What is the meaning of rifling?

noun

• The cutting of spiral grooves on the inside of the barrel of a firearm.
  • synonyms: grooving

verb

• Steal goods; take as spoils.
  • usage: "During the earthquake people looted the stores that were deserted by their owners"
  • synonyms: plunder, despoil, loot, reave, strip, rifle, ransack, pillage, foray
• Go through in search of something; search through someone's belongings in an unauthorized way.
  • usage: "Who rifled through my desk drawers"
  • synonyms: rifle, go