Shoot into a safe backstop. Berm or hill is best - large tree will do in a pinch.
Better yet, use blanks or shotgun shells with wadding only. Still a good idea to fire at a safe backstop.
We had a case here in GA where a girl was killed on New Years Eve in College Park while standing in a parking lot . . . bad part of town, lots of guns being fired into the air, but it wasn't clear whether she was shot by a bullet falling or by a stray bullet fired parallel with the ground . . .
Firing live rounds into the air is sooooooo "raghead"! (We didn't need the Brady bunch to tell us that it is a bad idea...)
Better yet, use blanks or shotgun shells with wadding only. Still a good idea to fire at a safe backstop
It is a long-standing tradition in our family to fire a number of shots equal to the last digit of the New Year (five, this time...) right at midnight. However, we use 12-Ga. "Bird Bombs":
---------------------
Bird Bombs (See "All Purpose Ammo")
"Blasts an M-80 type projectile between 50 & 100 yards. Upon detonation, you will see a BRILLIANT white light with a THUNDEROUS REPORT!"
-------------------
(BTW, when fired several feet above them, trespassers find these a powerful incentive to depart the premises -- post haste!)