Thanks for the links. The RAND paper is really good; the Reuters article less so. While your summary seems true, I think a better summary might be "despite many studies, none have found evidence for a full substitution effect". That is, in studies that show a drop in firearm suicides, there is almost always a drop in overall suicide rates as well. The degree to which changing from an existing lax gun control regime to a stricter one results in a lower firearm suicide rate is harder to establish, but in at least some cases for some populations it's probably a positive effect.