And for the record, here's how to attack the handguards on an A2 for those that were never issued one:
The delta ring is way too stiff to push the whole delta ring straight down.. You have to just tilt it enough to get one handguard off at a time.
Ensure the rifle is clear GI5 and set the butt on a solid work surface, muzzle pointing up. You want the delta ring about stomach height where you can apply the most leverage.
Choose a handguard to go after first. Upper or lower, doesn't seem to make much difference. Face that handguard toward your weaker side. With your weaker hand, grab that handguard just above the delta ring. With your strong hand, make like an "OKAY" symbol with your thumb and forefinger. Slide those fingers over the delta ring so that the tips of your thumb and forefinger are grabbing the delta ring behind the handguard you're trying to remove. Get a good firm grip.
Now lean on that strong hand and pry downward on that side of the delta ring only, where your fingertips are. You're not trying to press the whole ring down, just pry down that side only. At the same time, pull outward on the base of that handguard with the weak hand. With the right leverage the delta ring will tilt down enough to let the base of that handguard slide out.
Now turn the rifle 180 degrees, use the same hand positions, and repeat for the other handguard.
Installation is the reverse process.
HTH