The Selsey Coastguard and Rescue Team was called to the incident at 1.13pm today (Monday, January 28).
The ordnance was located, photos were sent to the coastguard’s operations room and the beach was closed.
The Royal Navy E.O.D. (Explosive Ordnance Disposal Team) arrived before a controlled explosion was carried out.
The beach was then reopened and the team were stood down to return to station.
Selsey Coastguard said: “Ordnance comes in all shapes and sizes and previous ordnance found on this beach has been found to be highly explosive so please do not touch it and dial 999 and ask for the Coastguard straight away.
“In an emergency out at sea, on the beach, or along the coast dial 999 and ask for the Coastguard.”
This is the second time ordnance has been found on Medmerry Beach in three days after a controlled explosion was carried out at 9.36am on Saturday (January 26).