Bandolier or Cartridge belt
A belt worn over the shoulder and across the breast often for the suspending or supporting of some article (such as cartridges) or as a part of an official or ceremonial dress.
Borrowed from Middle French bandouliere, probably borrowed from Catalan bandolera, a feminine noun derivative from bandoler "highwayman, bandit".
Bandolier. Merriam-Webster dictionary. Retrieved from: https://www.merriam-webster.com/dictionary/bandolier