That's the truth, for sure! Another example (around these parts anyway) is when someone says they have a "7mm." Nowadays that almost always means they have a 7mm Remington Magnum. However, in my youth (before anyone had even heard of the 7mm Remington Magnum) when someone said they had a 7mm, they meant they had a 7mm Mauser.
Then there was the time back in the '80s when I was telling a guy I knew at work that I had just bought my wife a 7mm-08 for her birthday. His response - "Now, what's the difference between a 7mm-08 and a
regular 7mm?"
Of course, there's always those folks that shoot 7mm Weatherby Mags, and even a few that shoot 7mm Shooting Times Westerners or some flavor of "Short" 7mm Magnum. But those guys almost always add the words "Weatherby" or "Shooting Times Westerner" or "Short Magnum" to their descriptions because, like you said, "it's critical."
Oh, and I also have a XP-100 chambered for the 7mm IHMSA (International Handgun Metallic Silhouette Association). I've gotten a lot more than one quizzical look from "regular" 7mm guys when I told them I have a 7mm IHMSA - especially when I tell them it's a "pistol."