Gun violence proposals are ineffective because more guns mean less crime
The "more guns, less crime" theory is based on severely flawed research
The research that put forward this idea has been thoroughly discredited. A 2012 report from the Johns Hopkins Center for Gun Policy and Research noted that a panel of experts from the National Council of Research and other experts found the “more guns, less crime" thesis to have "serious flaws":
A large body of research has been conducted to investigate the effect of RTC [Right To Carry] laws on violence. Most notably, research led by John Lott, Jr. suggests that RTC laws have led to significant reductions in violent crime. But the research showing crime-reducing effects of RTC laws, including Lott's, has been carefully reviewed by a National Council of Research panel of experts, and others, and has been found to have serious flaws. The most consistent finding across studies which correct for these flaws is that RTC laws are associated with an increase in aggravated assaults. Using various statistical methods, estimates range from a one to nine percent increase in aggravated assaults as a result of RTC laws.
A 2003 Stanford Law Review article by Ian Ayers and John J. Donohue III found that Lott’s co-authors “seriously miscoded their new county dataset in ways that irretrievably undermine every original regression result that they present in their response.”