It’s about time Californians were able to use detachable magazines

CA Law

California Definition of Assault Weapon

12276.1. (a) Notwithstanding Section 12276, “assault weapon” shall also mean any of the following:

    (1) a semiautomatic, centerfire rifle that has the capacity to accept a detachable magazine and any one o=f the following:

    (a) pistol grip that protrudes conspicuously beneath the action of the weapon.
    (b) thumbhole stock.
    (c) folding or telescoping stock.
    (d) grenade launcher or flare launcher.
    (e) flash suppressor.
    (f) forward pistol grip.
The following definitions apply to terms used in the identification of assault weapons pursuant to Penal Code section 12276.1:

(d) “pistol grip that protrudes conspicuously beneath the action of the weapon” means a grip that allows for a pistol style grasp in which the web of the trigger hand (between the thumb and index finger) can be placed below the top of the exposed portion of the trigger while firing.


The U15 is not a “pistol grip”.  The U-15 stock makes it physically impossible to get the web of the shooter’s hand below the top of the exposed portion of the trigger.
(e) “thumbhole stock” means a stock with a hole that allows the thumb of the trigger hand to penetrate into or through the stock while firing.


The U15 is not a “thumbhole stock”.  The U15 stock does not have a hole.

When the U15 rifle stock is attached to a rifle that does not have a flash hider, and does not have a forward (vertical) grip under the hand guard, the rifle is not an assault weapon and it may use detachable magazines.

Muzzle Brakes are okay.  Click here to see how to identify a Muzzle Brake vs. Flash Hider. (link coming soon)

The U15 Stock Kit – Retail Price: $205 + shipping & tax

  1. U15 Stock pre-assembled with John Masen recoil pad
  2. Receiver Extension
  3. Receiver Extension Foam Tube by ACE Ltd.
  4. Receiver Plate
  5. CAR Buffer
  6. CAR Buffer Spring
  7. Socket Head Cap Screw to attach the stock to the receiver.

The U15 Stock Kit requires no modification to your AR-15 rifle or receiver.  The complete kit installs and uninstalls in minutes and requires only the same 3/16” Allen wrench used to uninstall the pistol grip.

The U15 stock is manufactured by Matt Shuster of Ironwood Designs in San Jose, CA.
It is cut from very hard European beech wood and painted with black textured epoxy paint by Top Line Applications in San Jose, CA.

The U15 bracket is machined in San Jose from T6 grade aluminum and hard-anodized with a black finish.

The receiver extension is designed for AR-15 pistols.  It is the same length as a CAR receiver extension except is has extra room past the threads to accommodate the receiver plate.