Though it is difficult to ignore the possible unconstitutionality of requiring a permit to exercise an enumerated right, some states require residents to obtain a permit before they can purchase a handgun (or any gun). But do these permits make any difference? Some activist groups say so. Some academic studies say either yes or no. That a minimum of 43% of crime guns come from underground markets would indicate any effect would be marginal. After that… it gets complicated. Takeaways Permit-to-purchase laws have no material effect on gun homicide or suicide rates. The 1993-era anti-crime legislative movement limits pure test cases. A Dearth of Data Permit-to-purchase (PTP) laws have been touted as preventatives for homicides, suicides and gunshot injuries. We can measure the first two, not the last.