No, he doesn't know the difference. And anyone who doesn't know the difference shouldn't be posting on this forum. Bullets are to cartridges as flour is to bread as cement is to concrete, etceteras. They may not have the capability of learning the language.
If FR were solely a firearms forum, I'd agree with you, but it's not. There are over three hundred thousand people with Freeper accounts, and not all of them have basic firearms education.
Why not give them a hand up, and help them to raise their knowledge level on firearms? We're all in this together.