There is no universal "rule" for naming cartridges. One of the more common themes is to name a caliber based on the bore diameter, which is the size of the hole drilled into the barrel prior to rifling. It fits the 270 Win, various "30 caliber" rounds, and most 7mm cartridges. Going by that theme, the 44 magnum is more like 42 caliber than 43 or 44.

One round I always wanted to try is the 7-30 Waters, but guns chambered for this round are not common. Maybe someday I'll find one, or have one made. Until then, I'll stumble along with my outdated 7x57s. wink

Our God reigns.
Harrumph!!!
I often use quick reply. My posts are not directed toward any specific person unless I mention them by name.