Sure, we would probably have to build more prisons and have to pay higher costs to house these additional inmates, but would the prison costs outweigh the costs we currently pay for repeat offenders to the police, the courts, probation & parole officers, insurance companies, victim assistance programs, medical professionals (including mental health), increased security costs, the emotional costs paid by the victims……. and on, and on….? Tougher sentences may not completely deter people from committing violent offences, but at least that particular person won’t be out on the street to commit any other offences.
No, guns don’t kill people, but violent people with no regard for life do, and since we can’t rid the world of all guns (legal or not), let’s lock up violent criminals who use them for a long time.