I noted yesterday that the online source where I bought mags for my M&P full size (10 rounders) had no M&P mags, period. Don't know if that is because of the recent demand, or for other reasons. 10 round mags were legal during the last flirtation with draconian laws.
Even before this tragedy in Connecticut, I checked my favorite online private firearms listings the day after the election. I noted a seller in the Midwest listed his M&P 15, nothing special such as as decent optics or a jillion mags or a boat load of ammo for $1300 m - about $350-400 over priced in my opinion. The run was starting even before this incident. Now its even worse.