Some people say,
"Guns don't kill people - people kill people."
But those same people would agree that
"you shouldn't bring a knife to a gun fight"
"the ONLY thing that stops a bad guy with a gun is a good guy with a gun."
And you would never hear any of them say,
"That's so easy, it's like knifing fish in a barrel!"
Guns are easy to use, readily accessible, and lethal at range. Their prevalence therefore increases the homicide and suicide rate above what it would otherwise be. After Australia put tough new gun regulations in place and launched its gun buyback, homicides overall fell, even though they only had around 25% of all homicides associated with firearms*. In the USA, homicides by firearm account for around 70% of all homicides, so we could see a bigger effect - provided we take the action.
*Caveat, as always, that correlation does not equal causation. It could still be possible that the drop in homicide is unrelated (even though they also show that there's been a simultaneous drop in the proportion of homicides involving firearms).