[GeorgiaDawg32]

Unless someone is in immediate proximity to an active shooter, it is NEVER a good idea to take your gun and go looking for him/her. LEO WILL mistake you for the shooter and you’re in deep doo doo then.

1) Hunker down
2) Ensure you have proper cover
3) ONLY fire if the shooter is headed your direction and is closing in.
4) Leave everything else to LEO.

[Mr Rogers]

When I carry, I have either a 5-shot 38 revolver or a 5-shot 22 derringer. Either way, it is a last ditch self-defense weapon to protect me and my family.

This is NOT what a sane person uses to go hunting a guy with body armor and multiple weapons, particularly if any cop in the area might mistake him for the bad guy: