Internal, caliber specific locks are more secure and effective than external designs.
All calibers are MD and CA DOJ approved.
The lock you are bidding on is for a .233/.5.56 Nato Caliber Rifle

    Rifles are locked through the breach, with a small ball-torxs key,  bypassing ejectors

•     Gun Friendly – all materials used are softer than ammo brass
•     ENDS ACCIDENTAL DISCHARGE
•     Great for transportation·     
•     Internal design does not interfere with handling