As the Staff Sergeant observed today,
by Paul 
, Thursday, August 20, 2015, 21:25 (3387 days ago)
few things teach you as much about a weapon as building one yourself. Yep, we threw together an AR 15 lower receiver today. Neither of us is impressed (favorably) with the Golden State's "bullet button" thingy-ma-jig. Next step (for him) is the building of an upper... once funds become available for such an endeavor.
I bought a bullet button for road trips to CA
by brionic 
, Thursday, August 20, 2015, 21:53 (3387 days ago) @ Paul
It works OK, but make sure to have the button release key nearby "just in case".
I found the C-Products 10 round stainless steel mag to be an effective choice in case I had to throw the castrated weapon at a goblin while drawing my pistol. Just kidding, sort of.
After futzing around with the setup, and then wanting to switch it back to the standard mag release just east of the AZ or NV state line, I gave up and went back to traveling with my Marlin shorty .44 and haven't looked back.
Living in state it's a different question.
Still and all, a fun project for you to work on two-gether.