Guns for self-defense is a bad idea. Those who own guns are statistically nearly four times as likely to die from gun-related causes than those who do not (mainly through impulse suicide, accidental shootings, and 'upping the ante' or freaking out others by pulling a gun on them, causing them to shoot first).

Sources:

http://annals.org/aim/fullarticle/1814426/accessibility-firearms-risk-suicide-homicide-victimization-among-household-members-systematic

https://www.hsph.harvard.edu/hicrc/firearms-research/gun-threats-and-self-defense-gun-use/