Adds option to lock the bolt open to show clear
installation instruction:
1. push in the bolt hold open into the front slot of the factory top rail
2. remove the factory charging handle screw
3. press on the extended charging handle nob on the factory charging handle
4. install the included new screw to secure the extended charging handle nob.
 
you can hold down the lock open arm with thumb or index finger while pulling out an empty magazine, or depress it with middle finger while pulling the handle back.