Earlier quoted context omitted.
Just making suicide slightly more difficult dramatically reduces suicide rates. It's difficult to stop someone determined to kill themselves, but most suicides are impulse decisions, so removing the opportunity often prevents the suicide. That's why suicide barriers on bridges actually reduce suicide rates rather than changing the method.
I agree with you generally… but in this specific case, do regions with very strong and effective gun control have dramatically lower suicide rates than the US? My understanding is that suicide rates in Europe aren't dramatically lower, though they do appear to be a bit lower in western europe and higher in eastern… I can't tell if this might be handgun related, is the delta large enough? http://en.wikipedia.org/wiki/…
But this is a tough thing to compare, as you note. Suicide rate is encompassing a whole bunch of things. I'm tempted to compare against Canada, where the suicide rate is only less by 1 per 100,000 people per year, but I have no idea if I'm picking that out fairly.
http://www.who.int/bulletin/volumes/86/9/07-043489.pdf suggests that the US is the only country where firearm is the preferred method of suicide. A bit morbid to read but there you go.