Small to none. You would have better luck at a local machine gun. Harbor Freight might have one, since they import everything from China, but a for warning they suck. They are cheap on Amazon and Ebay.
Here it is on Amazon.
I mean, technically it's not a firearm part here is the die from Amazon by itself, and here is a kit that doesn't appear to have issues shipping to CA. Looking at other stuff on their site there are CA bullshit warnings on same stuff. It is literally a die, handle, piece of metal with good threads to start, and some cutting fluid.
http://www.amazon.com/gp/product/B007FK8O56?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00 It's worth the $21 shipped if you do a lot of tech work.