ANYONE possessing AR style weapons, please read this.
@kenny42 In another post you mention about having to be an amateur lawyer in order to own a firearm in CA, and it's true for the most part. But I wanted to caution you on the Rattler, because ARs are a different story than a Glock. It wasn't until recently with the cruucifix changes that Glocks even got on the radar, but ARs have been going through this attack for 30+ years. And California has taken it to the extreme, on both sides, it seems that the courts in CA continue to find ways to stop the ownership, legally, but the residents come up with some of the most fascinating work arounds to those evil techniques.
Short barrels are a definite concern in CA, and even though I own a bunch of them, it's unclear how we need to have that configured on an AR in order to stay out of jail. Butt stock on an AR, be it pistol or rifle, is a concern, as an adjustable butt stock was a no-no at some time. At one time we had to use a "Bullet Button", to be legal, but my understanding is we're allowed to have a regular mag release nowadays. There was a case in TX that ruled on pistol braces. Everyone needs to understand that, because nobody has been charged in CA for a pistol brace, yet, but I don't doubt they would do that.
Most of the law enforcement is on the resident's side, but they need to uphold the law, and this causes tension.
I don't know enough about your Rattler to know if it's legal as-is or not. I do have some 16" barrels and AFAIK, we can have a standard AR configuration, sans the flash hider. A flash hider is one of the evil features we're not allowed to possess, so if you want a device you need to use a brake.
I have some "featureless" stocks, Those are stocks that do not possess any of the evil features that these so called Assault Weapons and Weapons of War.
And the grip is one of the evil features, you're not allowed to own a pistol type grip, so here's another workaround to solve that, over the years.
Here is one similar and one with a featureless rifle stocks (Thordson) This has a 16" barrel on it, so this is legal in CA, and the one below has the same grip which keeps the web between your thumb and first finger above the top of the grip. Both of these ARs are in 8.6 blackout, so this is to show 2 legal examples in CA that can be used. Notice the cheek weld on the pistol, that is also from Thordson, and it keeps you from extending the butt stock, there isn't one. There was a period where RSOs would question if you touch your shoulder while shooting, that is illegal per the books. The pistol grip is made by Sparrow. I hate them, they are one of the most uncomfortable grips on the planet. It is ok to use a pistol grip? Another grey area.
I really wanted to just explain to you the complications of owning a so called assault weapon.
At one time it was thought if you were a member of one of the organizations that filed in TX, you have an injunction against the state of CA from arresting you, but the state says otherwise. Once again you'll need to be an amateur lawyer, and this is yet another one of those areas...I have not heard of anyone being arrested over a pistol brace, but Newsom/Bonta are saying we can't have anything with a short barrel period. I think they would charge us with a short barrel, not the stock.
This is a long post, but this is to say, be careful in CA, there are many traps that they will not charge you with directly, but if you're in possession of an evil device, you might be charged for just possessing it.
If you really want to be confused, here's an 8.6 blackout that I don't have configured anymore, the lower is locked in a safe. I don't think this is legal, for nothing other than it has a 12" barre with a brake.