There is no "bit different" or "here", because I am in the UK as well. I know nothing about guns, but know about both the Walther PPK and the 44 Magnum. They are iconic parts of those films. Everyone knows about those guns and could tell you what guns James Bond or Dirty Harry carry.
The 44 Magnum is also a major plot point of some of the Dirty Harry films too (eg Magnum Force) and he also says an iconic line in Dirty Harry that everyone knows: "This is a 44 Magnum, the most powerful handgun in the world, and would blow your head clean off."
If you don't want to use the Delorean example, then take something like Starsky and Hutch. People know that they drive around in a red and white striped Ford Gran Torino. However people in the UK have probably never seen one in person.
It's like knowing what cocktail James Bond drinks even if you don't drink yourself. Everyone knows it's a Vodka Martini, shaken not stirred.
Arguably some of the other guns people have mentioned in this thread are ones which people wouldn't know the make of but would just say it's the gun from such and such a film. But people know James Bond's gun and Dirty Harry's gun. They transcend gun knowledge (or lack of knowledge).