Okay kiddo, let's talk about the 1-inch Nordenfelt gun! It's a fancy name for a type of gun that was invented a long time ago, back in the late 1800s. It was a big gun that could be put on a ship or a boat, and it was used to shoot at other ships or boats during battles.
The gun got its name from the man who invented it, his last name was Nordenfelt. The gun was made out of metal and had a long barrel that was about one inch in diameter. That's why it's called a 1-inch Nordenfelt gun!
To use the gun, you had to load it with special bullets that were made just for that size of gun. Then, you would aim the gun at your target and pull a lever, which would shoot the bullet out of the barrel really fast!
The 1-inch Nordenfelt gun was a big deal back then because it was one of the first guns that could fire a lot of bullets really quickly. This was important during naval battles because the faster you could fire your gun, the more damage you could do to the other ship.
So, that's basically what a 1-inch Nordenfelt gun is, a big gun that was used on boats and ships to shoot at other boats and ships during battles. I hope this explanation helped you understand it better!