Revd Hedges: To kill such a creature will require nerves of steel and…a bullet! [lightning]
Quartermaine: A bullet? [lightning]
H: A bullet! [lightning]
Q: A bull… [lightning] Oh! [exasaperated, closing the window] What kind of bullet?
H: A bullet… of pure gold.
H: Yes… 24 “carrots” [chuckles, with a slight tinge of insanity]
– From Curse of the WereRabbit
Wallace and Grommit is perhaps on the edge of speculative fiction, but everyone loves a long suffering dog and a bumbling inventor, am I right?
There’s a strong tradition that silver is sovereign against the undead (or at least certain segments of that population). The use of gold in ‘Wererabbit’ is mainly to allow that one gag, but to be fair, it is completely worth it.
But could you really make a bullet out of 24 carrot gold?
Today’s digression. 1) It’s actually spelled carat. 2) Properly speaking gold is measured in karats and diamonds and other precious stones are measured in carats. The two have come to be treated as variants of the same (mainly in the direction of gold rather than karats for diamonds), to the extent that most news outlets and even some jewellers use carats for the fineness of gold.
We could get distracted by the etymology of karat/carat, which could take us back to ancient Roman coins and carob seeds, but I’m going to resist that urge. What it is worth saying is that when it comes to the fineness of gold, 24 karats is the most pure that you will commonly find, but it is still only guaranteed to be 99.9% pure (three nines pure), not 100%. Sometimes four nines, five nines and even six nines fine gold is produced for special or commemorative coin issues, for example. 24 karat gold is expensive not only because it is so pure, but because that purity is difficult to achieve. 22 karat gold is 91.6% pure (and as a side note, this means that sterling silver is more pure at 92.5%), 18 karat is 75 % pure and so on down to 9 carat gold at 37.6% purity.
The problem is that very pure gold is so soft that you can’t do anything useful with it in a structural sense. So in the case of jewellery, whilst you will find necklaces, bangles and the like made from 22 karat gold, settings for stones need the harder, less pure 18 karat gold. It does have some resistance to deformation having a modulus which is similar to aluminium, but it has only about have the strength. One of the factoids that crop up about gold is that 1 g of gold can be beaten out so thinly that it covers 1 square metre, which is useful for jewellery, decorating and cookery (E175, if you’re interested). The reason that you can do this is that gold doesn’t work harden. In most metals, defects in the crystal structure begin to interact when you hit it and make it more difficult to modify it further. This doesn’t happen with (very pure) gold, because a) there are more slip planes (directions in which defects can move) available than in some other metals b) there are fewer defects because there are fewer impurities and c) there are few impurities to get in the way and disrupt the crystal structure (the difference between the last two points is subtle and unfortunately I don’t have the time to expand on it here).
So can we use golden bullets? Wouldn’t they be too soft? For this we might want to look at another instance of gold in ballistic weaponry – the Man With the Golden Gun. Like Bond himself there is more than one avatar of Francisco Scaramanga, and indeed his eponymous shooter. In the books he is a hire-powered gunsel who effectively works for the Mob and has a Colt .45 Peacemaker and a back-up Derringer, both gold plated. The Colt shoots silver jacketed bullets, with a gold core. In the film he has a custom made ‘gat’ and custom made 23 karat gold bullets. (Sources vary as to whether the pistol, or rather the component pen, cigarette lighter, cigarette case and cufflink, are solid gold or gold plated, but given everything we’ve said above, I think a solid gold gun would deform to the point of inoperability before use, and should it ever be fired would probably blow up in your hand).
Here we do just need to take a moment to consider the structure of a bullet or, strictly speaking, a round or cartridge. The bullet is the bit that is fired from the gun, but in order to accelerate the bullet you need to give it impetus. This is usually achieved by firing gunpowder, causing it to explode and create a local increase in air pressure which fires the bullet out of the gun. Traditionally the bullet is lead, but modern rounds are usually ‘jacketed’, i.e. the lead is encased, usually in brass (hence in police procedurals, a professional shooter is indicated because he ‘policed his brass’ i.e. collected the spent cartridges). Other materials are used, but that’s a whole other A-Z.
So Scaramanga either uses a normal-ish bullet with the lead replaced with gold, which sort of makes sense if you’re some sort of show off, or he uses an unjacketed round where the bullet is gold. (Given that he uses a one shot weapon, he doesn’t have to take extra steps to police his brass, and presumably returns his empties to his armourer). Such bullets could work, but they would deform massively causing much more trauma than we observe in the film – the effects are sanitised for the audience, rather than providing verisimilitude. So called ‘Dum Dum’ bullets are commonly supposed to be banned by the Geneva Convention, but this is a fallacy. They are prohibited by the Hague Convention, and their use in international warfare is frowned upon, for whatever that is worth. The issue, is that on impact, such bullets can as much as double in diameter, causing significantly more damage, without necessarily killing someone outright. Andrea Anders (Maud Adams) would certainly not look that peaceful, and Hai Fat’s assistant would have a much messier job of clearing up after TMWTGG’s corporate takeover.
So a solid gold bullet is an expensive way of sorting out a giant rabbit problem, and an extremely messy one. I can’t speak to the supernatural effects, but there are probably easier ways of dealing with a wererabbit. You’re probably better off offering it a nice juicy carrot (or 24 of them) and relocating it. More cheese, Grommit?