Not a problem I understood that ie regarding barrels.

Here is Australia, we do not have a strict number restriction though that is slowly changing. I have more than two dozen firearms, rifles and shotguns. No handguns yet, though I can legally buy one or more. Only for target shooting though. It is getting harder and harder as they introduce more and more restrictions and increasingly difficult "justifications".

I have two Mauser M03 rifles with several sets of barrels. Good for travelling as the barrel can be removed. And I have barrels from .222 to .404 for them. I purchased a second M03 so I can have a medium and large bore on a trip or a small bore etc ready to go. Being takedowns they are shorter so also can be transported more discretely.

Same as a double rifle or shotgun, barrel out, the whole package fits in a smaller case.

I also have a Tikka/Valmet double rifle / shotgun setup, with two double rifle barrels, a shotgun set and a couple combination sets of barrels. Again the versatility.

Officially only one barrel needs to be registered with a receiver for a firearm here.