A friend and I were in a debate about gun laws a while back, and I was wondering if anyone here could clear up some points for me. (These are all hypothetical)

1) Are juvenile records used to determine if an adult can buy a handgun?
2) If a juvenile was 302'd by their parents (not a court) at age 15, and has had a clean record ever since, can they buy a handgun as an adult?
3) Can 302's be expunged from one's record (juvenile or adult)?

Thanks in advance for your help guys.