I got a 7mm britsh cartridge of ww2.My q is that is has an arrow scribed on d bottom, what does this mean?

I got hold of a 7mm British ww2 cartridge, one used like the one from the Enfield. My question is that on the bottom it has an arrow stamped on it, what does this mean? thanks all.|||The broad-arrow symbol means something is property of the Crown. It is or was used on the uniforms of prisoners too.