18 is an appropriate age for your more traditional firearms (pistols, shotguns, etc.). 21 for more serious things (rifles, machine guns, etc.).
About 15, any younger and you'd be putting those around you at risk.
Maybe not an age restriction but a maturity restriction. Some kids are idiots and would accidentally shoot their face off or kill someone else. Guns are dangerous and should be treated very carefully and with care, giving something that can easily kill someone to a kid or immature person could result in something very bad.
14 to use supervised, and 17 to own.
Yes, but pretty loose. I think there should be a limit in order to prevent giving it to an infant, but once someone hits like 10 or so it's fine to shoot a gun, maybe even younger. It'd be nice if we could just do it based off of there maturity level.
When they can pick it up and use it properly seems like a pretty good minimum age.
On a range, no, I don't think there should be. Teens should be able to use guns for a range or for hunting. I've used guns several times before and I'm 16. Why would I want to support any restrictions on that?
I agree with varrack. At home on private property or on a privately operated gun range it should be up to the parents/owners discretion. As far as carrying them in public on their own to wherever they are going ... the way the law is now is just fine. 18 for long guns ... 21 for pistols.
Owning a gun, yes. Shooting a gun, no. Common sense would automatically tell you to wait until your child/user is mature enough. I started shooting my AR15 on ranges when I was 10.
We're all entitled to our Constitutional rights.