Its real, its supposed to read as "Penetration with Blast" but they used the Latin "cum" instead of "with" to sound fancy. I can't fathom how this didn't get changed, like most people who worked on this would have spoken English and someone must have pointed out how funny this sounds.
It's for an Indian tank, so it's possibly something that's retained the initial meaning there.
It is very common to see this use of the word in India. "Cafe-cum-restaurant" "Playground-cum-festival ground"
"Get down, fool! That tank is targeting our position!"
Two outlines vanish into the rubble. Half a mile away, the whine of servos accompany the rotation of a four ton tank turret. As the cannon levels out, the sergeant can faintly make out the letters 'PCB' stencilled onto the side of the barrel. He swears.
"Are we gonna die, sir?"
"Worse."
