Here in Canada (where we supposedly like restorative justice and giving people second chances) the penalty for murder is life in prison.
The non-parole period (the amount that must be served) is set by the judge at sentencing and ranges from a minimum of 10 years for second-degree murder. (The longest period is never: indefinite incarceration until proven to be safe around others -- mostly reserved for serial killers.)
That is to say: the absolute shortest sentence you can get in Canada for murder is ten years.
In America I believe it's often many decades if not the death penalty, no?
Even Norway - renowned for the progressive humanity of its legal system - mandates at least 8 years jail for murder.
In just about any country anywhere 10 years for murder is, objectively, a relatively light sentence for murder.
Not at all sure what the sentencing for murder has to do with firearms, really. Other than firearms being an effective way to murder. Most murders in my country are beatings and stabbings, probably since firearms are not as widely available. Does that prevent a few? Probably. Still seems non sequitur.