i havent seen numbers, but your probably right, im sure a decent amount of guns used in crimes were bought legally at first and stolen. im actually very curious to know where the majority of guns used in crimes come from..
and no, we do an absolutely horrible job of controlling our borders, we have almost 1 million illegal immigrants entering the US per year, and our ability to control the drug trade is a complete joke. its obviously not hard to get anything over the border, so id say its pretty safe to assume that banning guns would create a HUGE demand for more illegal gun trade, if anything it would become more sophisticated and effective, and if anything bring a lot more violence along with it. we have far too big of a gang and crime problem for the illegal gun trade already going on to just stop. If the US suddenly legalized marijuana, regulated and controlled it, would you not agree that it would pretty much destroy at least the marijuana trade between mexico and eliminate pretty much all of the crime and violence that goes along with it? it just seems like common sense to me, humans and drugs have absolutely no problem crossing the border, guns would not be any different, especially with a much higher demand.
those personal experiences were mostly just to show you my, or a typical gun owners point of view. guns have never been a source or cause of violence in my life, and its the same for pretty much every gun owner ive known. but we are the ones getting shit for the wrong doing of others, being labeled all sorts of things for having basically no involvement in the actual problem.
ill use the analogy someone used above with drunk drivers, while i maybe half agree that its not a great analogy,(though i will say, when you get drunk and get in your car, you are knowingly putting peoples lives in danger, id say at that point, yes, a car does become a dangerous weapon, whether or not you intend it to be) it does apply, and its probably a lot simpler for someone to understand who isnt seeing it from a typical gun owners point of view, and i dont know how else to explain it. we do obviously have a huge drunk driving problem, (10,000 people die as a result of drunk driving per year, pretty much the same number we see for gun related deaths) drunk drivers make up 1/3ish of all driving related death. Yet we are at least approaching this problem with the right idea, going after drunk drivers, cracking down on them, actually putting in a lot of effort to stop the people who drive drunk and the situations that lead to it. while with the gun issue, we are completely ignoring 80% of the problem and going after about 2% of the "problem" you never hear about cracking down on gang violence and inner city crime and culture.
its like going after the guys that never break the speed limit and havent gotten a ticket in their life and saying "your the problem with drunk driving, give me your keys" it seems absolutely fucking ridiculous to us.
thats what it feels like when i talk to someone who has no clue about guns and has never been around our gun culture, and listen to them tell me im a bad person for doing nothing wrong.
to answer your question, first of all i have to say banning guns would not come even close to destroying our gangs, you have to realize, canada has what? 5 or so actual BIG cities? most european countries have probably 1-3. the US probably has double or triple that of canada. and still plenty of other very population dense area's. you look at pretty much any of our major cities and there is a big crime, gang, and violence problem, all associated much more with the culture, poverty, drug trade, etc.. than they are with guns. if you want to destroy gangs you would need to crack down on the culture.
anyway, no i wouldn't agree to a complete private gun ban even IF somehow gangs miraculously disappeared. It's taking away the rights of tens of millions of completely legal, lawa abiding gun owners, for the actions of people they arent even associated with, so in that regard, i would be morally against it.
you can regulate the crap out of us, take away every right or privilege we have, and probably save millions of lives per year. but id rather live in a society where i have as much freedom as possible rather than a society that could guarantee my safety and a long healthy life. (not that taking away guns would do that) so, ASSUMING, for arguments sake, that a gun ban would completely eliminate gun death and gangs(which i think we can both agree would not happen) i would still be against it, because id rather live with the slight added risk, than loose the freedom.