I have seen many posts all over the net from people wanting to learn how to remove an AR15 A2 front sight base which is also the gas block. Having an older Colt A2 heavy barrel in need of a barrel nut change I was forced to learn how to do this successfully and thought I would share my experience to help others face this challenge. This is probably the hardest thing I have ever had to deal with on an AR platform. What I did was to first do my research and read every post I could find on the experience of others and try and figure out what the procedure was and also to learn from the mistakes of others. I learned I needed special tools and that it is no easy matter to get this done. So.... what I did was get a 12" 4x4 square piece of wood and a router bit about the size of my barrel dia. and then lay the stripped barrel, gas tube and upper removed, facing left side up, or muzzel to the left, chamber to the right on top of the wood block up to the hand guard retaining piece with the rest of the barrel and chamber end supported by a roll of duck tape of all things, on a concrete floor as a solid base. Then I took a sharpy and outlined the barrel on the wood. Next I took my drill and and the router bit and cut out a bed for the barrel and sight to lay in so it would not rotate when I got to the part about hitting the 2 pins with a hammer etc. I routered out deeper below each of the 2 taper pins so they had room to come out. I had bought a tempered hardened steel 3/32 Starret 800C cup faced punch, like the one Brownells sells and took a 3 lb sledge hammer and gave the first pin a rather heavy wack. It popped lose and you could hear the sound of it when it gave. I HIT IT DAMN HARD. Then I took a regular brass punch and finished driving it out. I did the same thing on the other pin and it gave, and came out also. I did not have to remove the sling loop during this process. I simply rotated it out of the way but I could have also routered a deep hole for it in the wood if I wanted too, but it was fine kind of hanging over the end of the 4x4. Once the pins were out, I sprayed on the WD40 and took a plastic headed hammer and hit the back of the sight post once and it came right off. I did make a few minor abrasion marks near the taper pin holes from the use of the punch - but they were quickly fixed with a cold blue pen. I then changed out the old barrel nut and reversed the procedure to drive the taper pins back in, to re-secure the front sight - this time from the right side of course. If you are putting on a free float tube rig, you would skip this step and install a low profile gas block at this point. I hope this information helps you to remove your A2 front sight, it's not as hard as some say - if you have the right tools and do your home work.