Telling her about a cartridge system (projectile+shell+gunpower, know as bullets nowadays) for instant reloading would have made sense. Telling her about a revolving bullet holding magazin or a spring magazing with shell ejectionsystem in the gun would have made sense. Telling her to made the projectiles spin doesn't make sense. Spinning projectiles have a more stabilized trajectory when ununiformly shaped and don't rotate the wrong way in flight as easily, but that should be a bit too complicated/to far of a leap for her. Why did she go "Ah!" about that, as if she'd know about it?
"Caveman, you've invented a torch. Any ideas on how you can make it even better?"
"Well, I could put the fire into a housing. Would make it easier to handle. I'd also need some sort of burning material, that can be replaced. A burnable fluid would be good to easily refuel it."
"Hmmm....How about we put a tungsten wire into a glasbulb, replace the air with inert gas and let an electric current run through it?"
"Ah!"