Leatum
The Laetum is an ceremonial pistol chambered in 50AE.Codex Entry:
"During parades and victory marches, the Laetum fired pigmented airburst rounds that rained onto festive crowds. The Orokin sent Laetum with the Zariman so they could properly celebrate a successful maiden voyage to Tau. There would be no such celebration, but the Void imbued the Laetum with a much more explosive capacity."
Credits: Warframe By Digital Extremes