The John Reed magazines are what you want.
jreedtn81@gmail.com
Buy once, cry once.
As for the nomenclature, refer to it however you like and call it what you like. You are right and the buttinskis are 100% wrong.
What is more their nonsense impresses me as immature, boorish and petulant attempts at grandstanding. It’s nobody’s business to monitor other people’s choice in that regard.
In the case of a Remington 581, Remington is who designed, built and offered the 581 and 541 to the public. Therefore they have every right to name it whatever they choose and they chose clip. They could have also referred to it as a donkey, and if they so chose to do so then someone who had a problem with someone asking about a donkey for a Remington 581 deserves to be told publicly to mind your own business.
So, if the self selected monitors of what others use can’t mind their own business then I feel perfectly comfortable telling them that they need to get a life and leave other people alone. No one appointed them Grand Monitor of Nomenclature except their own selves. They are 100% wrong, in a Remington 581 the name of the part is clip. That is the name Remington chose to use for the magazine in a Remington 581. To enquirer about a clip for a Remington is 100% legitimate and that is the 100% correct name for that part and there is absolutely nothing wrong with referring to that part by its name. NOTHING WHATSOEVER.
That being said, there is nothing at all wrong with referring to that part as a magazine for a 581. The part Remington chose to label with the name clip, is a magazine.