Excavations near Shute unearthed the device on Wednesday afternoon.
Royal Navy engineers were called to the scene and the shell, believed to be from World War II, was detonated on Strete Gate Beach.
The police wanted to reassure the public any explosion heard in the area on Wednesday night was nothing to be concerned about.
Alison Hernandez secures third term as police and crime commissioner
She'll continue tackling major issues on her to-do list
How Exeter's traffic troubles influenced council vote
LTN campaigner ousts Labour candidate
Labour tightens grip on Plymouth City Council power
They've gained nine extra seats
Radio Exe newsreader to abseil down Exeter Cathedral
Josh Tate will descend over 100 feet on Saturday
Labour retains control of Exeter City Council
Despite losing a seat to the Greens and an independent
