I see your Dr Langmann and I raise you actual peer reviewed sources.

1. There is evidence to suggest that firearms regulations can have a positive impact on reducing gun violence. Canadian Medical Association Journal found that the introduction of firearms registration and licensing in Canada was associated with a significant reduction in firearm-related deaths between 1974 and 2008 [1]. Similarly, a study published in the Journal of Urban Health found that a ban on military-style assault weapons in Canada was associated with a significant reduction in firearm-related deaths [2].

• [1] Canadian Medical Association Journal: https://www.cmaj.ca/content/185/16/E794
• [2] Journal of Urban Health: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2572212/

1. a study by the Canadian Journal of Criminology and Criminal Justice found that although the introduction of firearms legislation in Canada in the 1990s did not have a significant impact on overall homicide rates, it did result in a significant reduction in domestic homicide rates [3].

Sources: - [3] Canadian Journal of Criminology and Criminal Justice: https://www.utpjournals.press/doi/abs/10.3138/cjccj.57.4.409

1. a study by the Canadian Firearms Program found that legal firearms were used in approximately one-third of all firearm-related homicides in Canada between 2000 and 2010 [4].

Sources: - [4] Canadian Firearms Program: https://www.publicsafety.gc.ca/cnt/rsrcs/pblctns/2015-rdcng-dngrs-frrms/index-en.aspx