Hello Everyone
Calguns.net didn't have it's own "California compliant OLL assembly guide" to comply with California laws with either Prince50 or Bullet Button.
So with the help of a Calguns member this guide was set up to help with assembly of your Off List Lower.
It is your responsibility to know and understand the California firearms laws and to maintain your rifle in a California legal configuration. 
You can get most if not all the info here:  http://www.calguns.net/calgunforum/showthread.php?t=56818
It is important that you first install one of the locking methods before proceeding to any of the other parts/features of the rifle to conform with DOJ regulations.

Here are the tools I used

Here's a OLL (Off List Lower) when you buy it stripped.
 This is the actual part of the lower receiver with the caliber, model and serial number that has to be DROS'd through a FFL dealer. 
You will need a locking mechanism, either the Prince50 or Bullet Button, LPK (Lower Parts Kit) and Butt stock Kit
to be able to complete the assembly of your stripped OLL to be used with a upper assembly.

Here's a Bullet Button Kit

Here's a Prince 50 Kit

Here is a complete Stag LPK (Lower Parts Kit)

Step 1
California compliant magazine catch
Parts needed are magazine catch from LPK (Lower Parts Kit) and either Prince50 or Bullet Button Kit.
-Install the magazine catch on the left hand side of the receiver.-

To install Prince50
-To install with a Prince50 Kit insert the magazine catch spring and the magazine button that came with the Prince 50 kit on the right side of the receiver magazine catch.  (Careful not to scratch the left side of the receiver with the magazine catch while screwing in)-
-Hold the Prince50 magazine button in the hole while turning the magazine catch on the other side until the magazine catch is flush with the magazine button.-
-At this point if you are building with pistol grip, flash suppressor, retracting butt stock you must screw in the hex screw to lock the magazine button after the magazine is inserted.  Once locked test to ensure the magazine does not drop or come out in any way before proceeding.-

To install Bullet button
-to install with a Bullet Button Kit insert the magazine catch spring.  (Careful not to scratch the left side of the receiver with the magazine catch)-

-One end of the Bullet Button base (black anodized part) has a burr and didn't fit so I had to do some filing per instructions.-

Touched up after filing.-

-Insert the base into the receiver notched side down.-

-Insert spring and start the button screw.  You will need a small screwdriver to work the notches of the screw in.-

Step 2
Bolt catch
Parts needed will be the roll pin, bolt spring, bolt buffer and bolt catch.

-During this step you may want to tape the side of the receiver to avoid scratching it with some tape to protect the finish.-

-Start the bolt catch roll pin to hold in place, install the spring, then the buffer for the bolt catch.-
-Line up the bolt catch in place while installing the roll pin all the way through.-
(I used a pair of vise grips wrapped with electrical tape to start the pin then used a pin punch and small hammer the rest of the way)

Step 3
Trigger, disconnecter and hammer.
Parts needed will be the trigger, trigger spring, disconnecter spring, disconnecter, trigger pivot pin, hammer, hammer spring and hammer pivot pin.
(hammer spring and hammer pivot pin not pictured)

-Put the disconnecter spring inside the trigger and put the disconnecter on to the trigger.-

-Insert the trigger into the receiver lining up the holes of the trigger, disconnecter to the receiver hole and install the pin into place.-
-Insert the hammer with the hammer spring resting on the trigger pivot pin and install the hammer pivot spring.-
-Now function test the hammer manually verifying that the trigger locks back.-
-Carefully holding the hammer from slamming into the receiver and pulling the trigger to see if it releases.-

Step 4
Front take down pin
Parts needed will be the front take down pin, spring and detent

-insert spring and detent and hold with a blade type tool while installing take down pin.-

Step 5
Safety selector, Magpul CTR grip/trigger guard
Parts needed will be the safety selector selector detent, selector spring and grip/trigger guard.

-With the hammer cocked back insert the safety selector in pointing at the fire position.-
-Hold the selector to the safe position to ensure that the safety works.-
-Go back to the fire position and while holding the hammer carefully release by pulling the trigger not letting it slam into the receiver.-

-Insert the selector detent.-

*Instead of using the separate trigger guard and grip from the LPK (lower parts kit) I went with the Magpul MAID grip/guard.*
*But installing is pretty straight forward.*

-Line up the trigger guard hole to the receiver and screw in the allen screw supplied.-
-Insert the grip bolt into the grip from the bottom of the grip and start the bolt thread on the receiver.-
-Once grip is partially on insert the selector spring into the small hole on the pistol grip that will line up with the selector hole on the receiver with the detent.-
-Work the grip into place without damaging the selector spring and tighten the grip screw and function test the selector while hammer is cocked.-


Step 6
Butt stock, buffer retainer and buffer tube and rear take down pin
Parts needed will be butt stock, buffer retainer spring, buffer retainer, buffer tube, buffer plate,
buffer castle nut, buffer spring, buffer, rear take down pin, rear take down pin detent and spring.

-Insert buffer retainer spring and buffer retainer.-

-Screw in the buffer tube unit close to the buffer retainer.  (Do not tighten the tube against the buffer retainer where it no longer moves up and down)-
-Push buffer retainer down in place and turn the buffer tube to hold the buffer retainer in place.-
-Insert the rear take down pin.-

-Insert the take down pin detent and detent spring.-

-While holding down the buffer plate screw in the castle nut and tighten with castle nut wrench or CAR wrench.-
-Now insert the buffer spring and buffer.  (May be easier if you cocked the hammer while doing this)-

Now you are ready to attached the completed lower to the upper!