I'm going to get into a question about variants. It's kind of on the same topic, but maybe it will become more clear.
The reason I ask is that it appears that the limit of five cartridges is redundant if the third part of the test simply bans firearms with detachable magazines, because there could be, at any time or place, a magazine that is larger than five rounds that fits the magazine port. That's the premise of what we're asking. There were similar questions asked about Butler Creek magazines a few years ago in terms of other similar magazines. Butler Creek magazines were prohibited, but these other particular and almost identical magazines were not.
It's a very confusing situation for firearms owners.