Although this could just be a case of monkey see-monkey do, I suspect we are seeing something new here. I think that we are seeing a more sophisticated and high dollar effort at gun control by Bloomberg and his Mayors Against Guns outfit, through their lobbying arm the Raben Group. They are using lobbyists in each of the states they are choosing as battlegrounds.
These guys are devious, sophisticated and well-funded and will stop at nothing to achieve their goals. For example, they have recently created a new arm of their movement, called protectpolice.org which has its own website and is dedicated to removing restrictions on local law enforcement access to BATFE databases.
They have had their finger in just about every aspect of gun control and CCW legislation across the country and one of their goals is to destroy the NRA's influence on legislators.
In my opinion this is a very dangerous group that poses a danger to our political system and our rights. They are all the more dangerous because of their benign name (I mean who supports ILLEGAL guns, and who opposes a bunch of well-meaning mayors?). You need to keep a close eye on these guys. This group is very active in state and federal lobbying, advertising, web presence and so on, and who knows how extreme their ultimate goals are.