I read it until I saw their methods included using models. You don't have to use models on your cherrypicked counties, unless you want to be able to manipulate your results by manipulating the models (garbage in/garbage out). Happily, they cite quite a few studies on the topic, one of which looked at the decade before and after loosening gun laws.

One of those is this: https://www.researchgate.net/publication/282442721_Concealed_Handgun_Licensing_and_Crime_in_Four_States

with this gem that made me stop reading as soon as my biases got confirmed LOL

changes in crime rates exhibit a number of patterns. Rape and burglary showed decreases across all four of our study states. Robbery, aggravated assault, and larceny increased in Michigan and Pennsylvania, with Texas and Florida showing mixed results for the rates of changes in these crimes. Murder decreased in Michigan and Texas

r/2aliberals is having none of it LOL https://www.reddit.com/r/2ALiberals/comments/15o9c1y/study_confirms_link_between_concealed_carry/