If you have a California misdmeanor conviction, you are in luck. California is more generous than most states when it comes to getting convictions off of your record. And they even have an expungement self-help center which is very helpful. I have linked you to the site. You should be eligible, but the site will also allow you to check your eligibility for an expungement and then will walk you through all the rest of it, step by step. California also provides all the downloadable expungement forms you will need to complete the process right there.
Navigating it is at first a little tricky. When you use the self-help link above and get to the home page, click on "Criminal Law" from the column on the left. Then click on "Cleaning your Criminal Record," scroll down towards the bottom of the page to the links and expand them so that you can see all of the steps.
An expungment is one of the few legal processes that does not require a lawyer.
If for some reason you turn out to be ineligible for an expungement, you would need to obtain a pardon from the governor. There is a 10 year waiting period before you can apply for a pardon, so you won't be eligible until 10 years after you've completed your felony sentence.
There are two ways to get a pardon. One would be to apply for the pardon directly to the governor of the state. The other would involve petitioning for a certificate of rehabilitation, which if granted actually turns into the application for the pardon, without you having to do anything further to accomplish that.you can read more about all of this and learn what you would have to do to obtain it here. If what you want is your gun rights back, the expungement will not be good enough to get your Federal rights back because of the Violence Against Women's Act and the Lautenberg Amendment. You will need the pardon also.