What does "gunge" mean?

Hello Everybody!

I'm watching a movie, called Money, which is based on Martin Amis's book.
There is a scene where I don't really understand what is the meaning of the sentence: "Gunge. Fifty-sixes. Automatics."
Can anybody help me with that?

Here is the text:

Driver: Only need about a hundred guys. A hundred guys like me. Take out all the n*****s and PRs in this fu..in' town.
SELF: A hundred guys? That's not many guys is it.
DRIVER: We could do it. With the right gunge, we could do it.
SELF: What's gunge?
DRIVER: Gunge, gunge, yeah. Fifty-sixes. Automatics. Well they think, you know, because you drive a yellow cab you must be some kind of as..ole.

Thank you for your answers in advance!

I can't find any definition, slang or otherwise, which would explain that exchange. I can only assume that maybe the driver was saying "guns" but with some kind of speech impediment which made the word sound like "gunge".

Thank you for your answer.
To be honest, I had the same thought, I just wasn't sure.
And is the "Fifty-sixes" supposed to mean the caliber of the gun?

Thank you again!

56-calibre does appear to be some kind of gun!

In the book, John Self has tinnitus, so he may not have heard it clearly.

Some of his books promise a lot and fail to deliver. This one delivered IMO- a great work.

Thank you for your answer.
Since then I found the book on the Internet, and the driver really says "gunge", but it still can be just a misunderstanding between John Self and the driver.

He does, but it comes directly after a reference to his tinnitus.

I've heard of authors giving their characters special dialects and accents before, but never of one capturing a hearing impairment like this.