Hangglider, as I read your comments 2 questions come to mind;
#1, why don't you move out of there?
#2 why are you not as well armed as the enemy?
An AK 47 is an excellent weapon and not very expensive. Put a B-square scope mount on it and a low powered scope and it's outstanding as a general purpose military weapon.
YES!!!!!! Get some training. Get training from a MILITARY standpoint! Not a police standpoint. Why?
You can't arrest anyone and you have no jail to take them to.
Secondly, it's got to be admitted that is the gangs have taken over your local government favored them, not you, which is WHY they have been successful in taking over in the first place. I'd have to assume that if you shot and killed a few of them, YOU would be arrested and go to jail. Correct?
That's because of "liberalism" in your government. There is no way around that argument, which leads me back to my 1st question
Why don't you move?
If your government is against you at the foundational level, and for the gangs at a foundational level, you CANNON ever 'win" the war. You may win a fight only to be targeted by both the gangs and the cops later.
Arms yourself and get training Yes yes yes.
But get the heck out of there as soon as you can.