Why so concerned about suicide? I can understand the negligent/accidental deaths when kids are involved but why suicide? Of all the serious circumstances which surround an individual choosing to end his or her life, you care about the tool used? It's so irrelevant.
Suicide is usually associated to a temporary state of low. You hit rock bottom, wanna commit suicide, oh theres a gun, 100% way to die.
Other methods take a lot more to actually get the guts to do it.
Tying a rope properly and pushing the chair
Jumping off a high altitude
Car accident impact...
Poison!?
And those methods have possibilities to fail. And also people are lazy, so if its just a temporary hunch... have to go through all the effort might be enough to change the person's mind.
Guns have a much higher probability of working.
If you fail, you have more chances of getting back on your feet and getting better than...well...if you succeed and die.
On the other hand..Guns are just VERY convenient to inflict damage as theyre made to be... easy to use to inflict as much damage. Creating a bomb requires more knowledge and is riskier than unloading a gun.
So lets just keep it at "ease of use is a big factor and efficiency is a big factor" in the "wrongful" usage of guns.
And no matter how much you say "the bad guys will find a way to get guns just the same" but the trick here is to NOT MAKE IT EASY for them to actually get them.
Just like drugs which are dangerous substances, there should be stricter laws around guns (in USA)... only makes sense.