Uganda: the heptagonal 5 shillings coin of 1972

[<k>]

Uganda issued a heptagonal 5 shillings coin in 1972. It was produced by the Royal Mint (UK) and was of the same size (diameter of 30 mm) and weight (13.5 g) as the large UK 50 pence coin of that time. Apparently most of the Ugandan 5 shillings coins were melted down. I do, however, own one, which is probably Very Fine in condition.

Was this 5 shillings coin a circulation coin? And why was it melted down? Does anybody know? Uganda was ruled by the dictatorial Idi Amin at the time, of course.

[FosseWay]

According to Numista, it was withdrawn from circulation, and most of the issue was melted as you say.

Logically if it was withdrawn from circulation, it must have been in circulation in the first place, but there is some room for doubt in terms of slightly vague use of language. (It could have been abandoned before being issued, for example.)

[<k>]

Logically if it was withdrawn from circulation, it must have been in circulation in the first place, but there is some room for doubt in terms of slightly vague use of language. It could have been abandoned before being issued, for example.

That's true. I do not know whether it was ever issued.

[Big_M]

Some seller claim that these coins could be found in the UK vending machines. Perhaps that was the reason for a quick withdrawal.

But then, why would the Royal Mint commit a similar error with the pound sized 1 lilangeni coin for Swaziland issued in 1986?

[Pabitra]

Many mints in international market do try to save on making fresh blanks when the customer is a distant land and size of tender too small. They have to win the tender by being the lowest bidder.

[FosseWay]

Some seller claim that these coins could be found in the UK vending machines. Perhaps that was the reason for a quick withdrawal.

But then, why would the Royal Mint commit a similar error with the pound sized 1 lilangeni coin for Swaziland issued in 1986?

There are several coins with the same specifications as the large size UK 50p. It's only an error if the detrimental effects turn out to be worse than expected/worse than the gains involved by using existing specifications compared to new ones. Mostly these overlaps occur with countries that are geographically distant and/or where travellers between them are likely to undergo significant customs checks and can be questioned if they are found bringing loads of 1 lilangeni coins into the UK. Basically, the risk from such imports is negligible. Of all the 50p-sized coins, the ones most abused must have been the Irish, UK, Channel Islands and IoM issues which could in practice be used in all five jurisdictions, which moreover are geographically near each other and have had customs agreements since long before the 50p was invented. If the problems arising from Irish 50ps being used in the UK weren't considered severe, then the occasional Swaziland, Tanzanian or Mexican coin must have been barely noticeable.

Also, (West) Germany didn't see any need to change the 1 DM coin for the entire 51 years of its existence despite it being close enough in size and weight to the UK shilling/large 5p for the latter to fool vending machines. This in a context where importing 5ps into Germany from the UK was physically easy and the number of people making the journey considerable. Presumably the fix would have been more expensive than just living with the problem.