The 9mm is not really a new modern cartridge. It hit the road about 1908. Looking at it and holding it in your hands , you could not tell it was rim-less cuz there is no rim.
You ought to admit you do not know what you think you know and learn more about what you have and how to operate it.
I did pause and look into the manual, after seeing that the 9mm case looked to have a thin rim or even be "rim less". The manual only directly talked about .45acp. It's was labeled 9mm on the barrel and the 9mm fit into the cylinder. Silly me. I won't be the only idiot to shoot the ammo without the moon clips.
If I hadn't dug into the back of the case to see what all was included, I would had never even noticed the three thin moon clips.