I think it's been posted several times already, but the reason we don't have good research on this topic is that gun advocates have helped to block funding for good research. I think that we all would agree that removing this roadblock would be beneficial for the debate.
I've never understood why people argue that there isn't good research available. The FBI numbers even include deaths by the "mass shootings" as well. Given that, the number of murders committed with firearms, even sorted by type of weapon seems rather good to me. Especially if you're looking to enact a ban on a certain type of weapon based on the misguided notion that that type of weapon is somehow being used on a more regular basis than others. It's not true, the data from the FBI doesn't support it, so arguing for it amounts to nothing more than fear mongering.
No, I'm saying that the ban makes getting good/less biased data hard. One group which was able to do a respective study said:
"Firearms account for a substantial proportion of external causes of death, injury, and disability across the world.
Legislation to regulate firearms has often been passed with the intent of reducing problems related to their use.
However, lack of clarity around which interventions are effective remains a major challenge for policy development.
Aiming to meet this challenge, we systematically reviewed studies exploring the associations between firearmrelated
laws and firearm homicides, suicides, and unintentional injuries/deaths. We restricted our search to studies
published from 1950 to 2014. Evidence from 130 studies in 10 countries suggests that in certain nations the simultaneous
implementation of laws targeting multiple firearms restrictions is associated with reductions in firearm
deaths. Laws restricting the purchase of (e.g., background checks) and access to (e.g., safer storage) firearms
are also associated with lower rates of intimate partner homicides and firearm unintentional deaths in children, respectively.
Limitations of studies include challenges inherent to their ecological design, their execution, and the lack
of robustness of findings to model specifications. High quality research on the association between the implementation
or repeal of firearm legislation (rather than the evaluation of existing laws) and firearm injuries would lead to a
better understanding of what interventions are likely to work given local contexts. This information is key to move this
field forward and for the development of effective policies that may counteract the burden that firearm injuries pose