Hi Guys, I had the chance to photograph these at work last week.
These were the 13mm anti tank rifle rounds developed by the Germans in 1918 to counter the new Allied tanks.
T67 = T round with a brass case made from 67% copper
P is for Polte, who made the round.
18 is for the year, with the other number indicating the month of production.
John Browning obtained some of these and they helped form his new .50 cal design.
These are inert.