The Kalashnikov rifle that the magazine design was copied from is a Prohibited fire-arm of the ‘safe queen’ variety. No person who owns one, with the proper endorsement on their licence, is permitted to take it out of the house, load a live round in it, transport it to an Approved Range, or shoot it, now and for ever.
Even so, the laws as pertain to magazines mean that mag.s of that design must be limited to holding five rounds. Even though the basis of that particular restriction is, for all intents and purposes, a non-firing display piece.
So it makes sense, but it doesn't. Get it?