Here's a California law firm's website explaining some of it.
Did you read the site that you linked to? The guy lays out multiple routes to success, including having a felony reduced to a misdemeanor. Like I said, if you're in the situation of our California speedster, you get an attorney and you get to work. When I said "easy fix" that meant relative to appeal to a clemency board. There are a number of people here yammering about "rights gone forever!" and those are clumsy polemics.
And some people here seem to believe that criminals have some kind of secret clubhouse the rest of us don't know about. Oh really? So if you're a law-abiding citizen, you have to shop at a gun store, but if you're a convicted criminal, you get a special membership card to Felonious Freddie's House of Black Market Firearms? To hear some people talk about it, once you're on parole, you are swimming in a world of $10 Glocks. Oh really? I don't think so.
But if that is indeed the case, as some here avow, then the punk convicted felon who is in fear of his life and desperately needs a firearm can just run out to the warehouse of blackmarket blunderbusses and load up with all the weapons he wants. You guys can't have it both ways. For the vast majority of Americans who go to work and pay their taxes, avoiding felony convictions doesn't seem to be all that difficult.
HL Mencken, in his epic Chrestomathy, has a number of essays on crime and punishment, and he noted back in the 40s that the prisons were filled with the unlucky. He made the case that most of us have done something or other at some point that could have landed any of us in the hoosgow. But you know what? I've found that in most cases DAs are pretty good about ignoring the obvious one-offs and they tend to prosecute people who show signs of being chronic, repeat offenders.
Indeed, we all know about the prominent exceptions to this rule because those cases tend to attract a lot of attention due to their rarity. Getting caught in the justice system is a hassle and it's always expensive, and those who've lost their rights are free to petition for their restoration. If that is an agrievement, it's a small one.