If American, realistically your best argument against gun control is the second amendment; if you're dealing with someone who "interprets" the second amendment then they're gone.
I've no other arguments to give you, but here are some observations which can be used to break down some of their "arguments".
In 2014:
>64% of firearm deaths were suicides.[1]
>Firearm homicides decreased by 3%. Suicides unchanged.
>You're 4x more likely to die of a drug-induced death.[1](Decent for bringing up the War on Drugs and how the "control" of those substances went nowhere, but guns aren't drugs so use with caution)
>Twice as likely to die of an alcohol-induced death.[1]
>9,278 homicide victims were male, only 1,730 were female.[1]
End 2014
Switzerland and the Czech Republic have roughly 6% of the firearm homicides that the U.S. has per capita. This suggests that homicide-by-firearm rates don't linearly scale with firearm numbers. There's actually a massive gap, suggesting the primary variables are something else.
FBI homicide data released in 2010 showed 17 handgun homicides for every rifle homicide.[2]
Compared to the firearm homicide rate, the successful use of a firearm in defense is estimated to be much higher, at 83,000/yr.[3] Sadly there aren't any great studies for this. Source 3 is a 20-year-old DoJ brief.
>[1] "CDC NVSR, Vol. 65 No. 4" cdc.gov/nchs/data/nvsr/nvsr65/nvsr65_04.pdf
>[2] ucr.fbi.gov/crime-in-the-u.s/2010/crime-in-the-u.s.-2010/tables/10shrtbl08.xls
>[3] "Guns and Crime: Handgun Victimization, Firearm Self-Defense, and
Firearm Theft", bjs.gov/content/pub/ascii/hvfsdaft.txt
If you bring up the ability for the citizenry to hold tangible power against government then make sure that you mention local and regional examples, such as the Battle of Athens (1946). People will find it easier to believe than the concept of fighting the feds.
Not all laws affect morally correct citizens, user.