Actually, I believe it would take 38 states to ratify any new amendments and that's after it would pass the U.S. House and Senate by 2/3 votes. A constitutional convention is something completely different and lets hope we never have one in our lifetime unless it's after we've had a leftist purge. Having said that, the left here will just do an end run buy using the executive branch to enforce the laws they like and ignore the ones they don't and their activist judiciary to find those actions (or lack of) consitutional.
As a general list of states to avoid for shooting puroses:
Massachusetts
Maryland
New Jersey
New York
California
Hawaii
I may be leaving one out off the top of my head but those are the states I can think of that have a patchwork of laws either severely restricting the number of gun stores and one's ability to get a federal firearms license, handgun registration & approval rosters (if it isn't on the roster it can't be sold), semi-auto rifle bans, and magazine bans on magazines over 10 rounds. In probably all of them except NY and MA you can go and rent a pistol at any range so all in all not too bad but don't expect to find too many outdoor ranges on par with the great facilities you guys appear to have on that side of the pond. Outdoor ranges are disappearing here faster than dinosaurs after a meteor crash due to encroachment by busy-body yuppies and soccer moms and the worthless politicians that cater to them.
The only places where handguns are defacto outlawed is in a handful of crappy cities throughout varouis states and it's largely ineffective as well as ignored. Chicago (and some of its suburbs) as well as Washington D.C. come to mind. Other than that you can pretty much own a handgun and store it in your home even in any of the above states I listed, it may just cost you more in time, money, and hassle to get it.
Speaking of handguns, I noticed one of the links somebody posted had a dealer selling an Argentine Ballester Molina under Section 7.3; would a Colt 1911A1 made in 1928 qualify under the same? Can guns that qualify under 7.3 still be imported? Just curious.