Your question is far to broad for the brief answers here. There are hundreds of State and Federal gun laws in each state. Please ask a specific question, and we will try to answer it.
Yes
The duration of Guns of the Law is 3360.0 seconds.
Guns of the Law was created on 1944-03-31.
Besides the obvious (don't go around shooting random people, airsoft on public or private property without permission, painting the orange tip of the gun, etc.), no.
TN does not recognize common-law marriages.
Federal law is 18 for long guns and 21 for hand guns.
There are no restrictions on handlebar height in TN. See http://university.apehangers.org/hbarlaw.php?state=TN
in the UK no
Federal law is 18 for long guns and 21 for hand guns.
GCA 68
No because it's against the law and you can be put in jail for buying guns.
Federal law says 18 for long guns and 21 for hand guns.