h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Your sons should be old enough to be able to understand that what they said has caused quite a bit of trouble and that they shouldn't do anything similar in the future.
You don't say where you live so not knowing local laws it's hard to know if the police would be interested in you having pellet guns at home.
Guns and shooting in themselves aren't bad, it is the way they are used that can cause problems sometimes.
If you are going to have guns in your home you need to make sure that young children can't have any access to them at all without direct adult supervision. They need to be stored seperately from their ammunition, and when being used they need to be treated with respect at all times, no "cowboy and indians" playing.
I'm sure that your immediate problem will blow over, kids will be kids, but you do need to be careful to make sure you prevent anything more serious happening in the future.

I would remove the guns as punishment for treating them with such disrespect. They have lost the right to such a privilege if they treat them as toys.

Guns don't belong in the hands of children.