In Burmese Days by George Orwell, when they are waiting to shoot the leopard, "Flory took four SG cartridges from his pockets and took Elizabeth’s gun to load it silently."
What is "SG cartridge"?
The story is about Burma in the late 19th century.
It refers to a size of buckshot in a shotgun shell.
Note the "Table of Buckshot Size" here:
000 or LG ("triple-ought")
00 or SG ("double-ought")
2 or SSG
The text of the book in English is online:
It looks like the events in question happen in Chapter 14:
(I wonder why the link to Chapter 14 has a "13" in it?)
It looks like they ran into a problem when it turned out that the guy only had birdshot in his pocket when he needed to reload the gun.
He fired again, and there was a fresh thump as the shot went home. The leopard gasped. Flory threw open his gun and felt in his pocket for a cartridge, then flung all his cartridges on to the path and fell on his knees, searching rapidly among them.
'Damn and blast it!' he cried. 'There isn't a single SG among them. Where in hell did I put them?'
The leopard had disappeared as he fell. He was thrashing about in the undergrowth like a great, wounded snake, and crying out with a snarling, sobbing noise, savage and pitiful. The noise seemed to be coming nearer. Every cartridge Flory turned up had 6 or 8 marked on the end. The rest of the large-shot cartridges had, in fact, been left with Ko S'la.
Personally, I'm not sure I'd want to hunt an animal as dangerous as a leopard with something as short range as a shotgun.
But that doesn't mean it can't be done I guess.
I've heard of professional hunters using a semi-auto shotgun loaded with buckshot to back up clients hunting leopard. But that doesn't mean the client was also using a shotgun. A professional hunter would only be bringing their gun into play if their client were about to be attacked, meaning that the leopard would always be within range of their shotgun in any situation where they would be required to use it.