One false argument I've dealt with is that many high-profile US shootings actually involved illegal acquisition of guns. This is actual bs. In case you come across a similar claim, here's a list of high-profile shootings involving legally acquired guns:
Parkland shooting 2018
Las Vegas shooting 2017
Orlando Nightclub shooting 2016
Sandy Hook elementary school shooting 2012
Virginia Tech shooting 2007
The list goes on and on. But these shootings were known throughout the world so these are some of the best examples in my opinion. Also see here for the statistic that [74 Percent Of Mass Shooters since '82 Obtained Their Guns Legally](https://gunsandamerica.org/story/18/11/02/since-1982-74-percent-of-mass-shooters-obtained-their-guns-legally/)
Please let me know if any of this is incorrect.