British World War 1, 18-pounder artillery shell cartridge case with a No. 80 Time and Percussion fuze used by the Royal Field Artillery. 
The base is stamped with 1915 and "18 PR" for 18-pounder also Marked as M.S.F indicating that it had been fired  & then sent to India to be refilled. 
The No. 80 Time and Percussion fuze was commonly used on 18-pounder shrapnel artillery shells, it was designed to detonate the shell in the air using a time-delay mechanism or upon impact using a percussion mechanism. 
The fuze has a rotating brass ring graduated from 0 to 22, allowing gunners to set the precise air-burst timing. 
Measuring 39cm with 10cm diameter