I had my own .22 rifle in my room when I was 12. It was my 12th birthday present. I had access to any gun my dad owned, but never touched them unless I was with him...in the 50's NO-ONE had gun safes, and NO_ONE worried about their children.
You had guns, you trained your kids on how to safely handle and care for your firearms, and what they were allowed to hanndle on their own, and what they were not...
Of course, Dr Spock...who never raised any children of his own, wasn't spouting his garbage back then either.
Your child, you do as you deem fit. I will make one statement, kids really like to be trusted...and if you are fair, they will Not violate that trust. Kid's are not dumb, and they are not crazy, unless you do not discipline them and let them do whatever they want.
We raised 5, and now have 14 grandchildren...I think I know a little bit about kids. A lot more than Dr. Spock and his ilk.