In several European countries, mere possession is a serious crime.
Simply touching munitions dug up in your garden can result in 10+ year prison sentences, as shown by the poor elderly lady sentenced to 10 years for moving 3 WWI or WWII cartridges from her garden to her doorstep, a couple years ago.
However, as I've pointed out in past threads, these draconian laws sometimes have an ironic unintended consequence- some people are so afraid of the legal consequences that they squirrel potentially dangerous munitions away in the proverbial deep, dark hole rather than surrendering them to the authorities.
Think about it. Let's say possession of pistol ammo is forbidden. You can be sentenced to prison for 10 years for possessing 50 rounds. Your father passes away, and you find a 1,000rd case in his garden shed. You had no idea it existed. What do you do?
I would also fetch my shovel.