This head stamp distinguish between ammunition made for military use and civilian use.
The manufacturer is, as writen above, IMI - Israel Military Industry and the meanning of the letters is as follows:
ת - Is the first letter of the Hebrew word for Manufactured
צ - Is the first letter of the Hebrew word for Military
The number is the year of production 1975.
Ammunition for the private market is marked: IMI 9X19 etc.
If this is a 7.62X51 mm ammunition, it is for use in light machine guns, sniper rifles etc.