Mag Ban Loophole?

[streak]

Here is my thought. If you check out Beyond556.com one of the most common thing for people shooting the 50 beowulf is to slightly modify a standard 30 round .556 AR mag to be a 10 round Beowulf mag. What would stop the mag companies from slightly modifying their standard mags in one way or another and then selling them as .50 Beowulf mags. And if they did do that would we as consumers get into trouble for stuffing 30 rounds of .556 into a 10 shot Beowulf Mag?