There are a few ways to remove the trigger guard on an AR-15.
The first way is to use a punch and drive out the two pins that hold the guard in place. You can also use a small screwdriver to remove the pins. Once the pins are out, you can pull off the trigger guard.
Another way to remove the trigger guard is to use a pair of pliers or a vise grip. Place the jaws of the tool around the inside of the trigger guard and then twist or squeeze until the guard pops off.
You can also try using needle nose pliers to remove the trigger guard. Finally, if you have an AR-15 with a detachable magazine, you can simply push the release button
You can also take a look at the video:
Martin Mapa Answered question September 9, 2022