If you're willin' to have the government order you to hand over your 30-round mags, what if I asked all polite and friendly-like for you to donate them to folks in other states whose governments have already stolen their liberty to own 'em? Send 'em to me and I'll buy a ticket for 'em on the underground railroad to put them in the hands of patriots to the Founders' Constitution to use if/when the masses ever gain a hair on its collective butt to fight tyranny with. Even if no such hair grows, those patriots can, will and do train for such a day, and their appreciation will be palpable even if non-directed to the right parties due to the necessary anonymity needed to keep the program running.
A now-deceased acquaintance of mine once said something to the effect of, "If government is bound and determined to turn you into an outlaw, be the best damned outlaw you can be." He didn't "need" all the 30-rounders he had either, and set about creating the aforementioned underground railroad so that he could put his "extras" in the hands of people having their liberty denied by their state governments. It's been quite awhile since I tried to donate, but send me all ya got and I'll find a way to help government-created outlaws be the best outlaws they can be.
Alternatively to sending your 30-rounders to patriots, you could send them directly to the tyrants who passed the laws in those patriots' states. The tyrants would then be in possession of banned mags, and subject to the same penalties (once law enforcement in their jurisdiction is notified of the delivery) as any subject...er...uh...I mean "citizen" of that state would be. We'll call it the same my deceased acquaintance did, "Toys for Totalitarians." There's even a pre-written letter there with just the right combination of acerbic wit, contempt and patriotic fervor that the deceased author wrote to his "targets." Don't worry. You wouldn't get in trouble for lifting the letter or anything. The author's dead. He's not using it anymore, and even when he was alive, I have little doubt that he'd have been thrilled, well, to death that anyone thought enough of his letter to use it themselves. So go for it. I can recommend some states where they would be appropriate to send to....
Blues