Semi + Centerfire = 5 round max
Ok.
semi auto center fire rifles are limited to 5 rounds...
Now...
Pistols are 10 so use a pistol magazine you have a limit of 10 if it's both rifle and pistol and they're semi auto it's 5.
Then you got bolt action, lever action, pump firearms. No limit unless the magazine is for both it and a semi auto.
Rim fire isn't center fire no limits only on handguns.
Designed and manufactured for is the important question not what it works in.
Alter the magazine and make it work then that's a no no alter the firearm and it works that's ok.
Now some magazines are exempt from the rules. The Lee enfield rifle is not more then 10 because they made a machine gun out of them and they didn't want to restricted the magazine because it was super rare (they break easy) so they said a lee enfield can be not more then 10.
Then you got things like the Luger snail magazine since they're rare they exempted them so you can have a 100 round magazine in a pistol and it's legal because people said hey this is super rare I'm not destroying it because it's historical that's why they have antique firearm laws that exempt them from being firearms so they don't get destroyed.
IT was also full auto collectors who said hey I can have a machine gun I can't legally shoot but the magazine isn't ok what the heck? So they exempted allot of them in the laws and if you read the law that exempts things you will find all the firearms on that list are prohibited now and good luck getting them.