I'm trying to remove the FSB but the taper pins won't buge. yes I'm doing for the correct side.
Can some one help?

Bushmaster? Try soaking them in CLP overnight. Then place a 1" thick board on each side of the FSB have someone hold the upper end and whack the piss outta them. Bushmasters are a bitch.

Oh yeah, that sucks. Might have to dremel it off...

i was in the same boat about 2 weeks ago. Ended up just having the smith take it off and assemble the upper from parts for 35$... well worth it imo and he warranty's his work too

Try this too.  Give them a couple of good whacks in the opposite direction.........yeah, that's right......... as if you putting the pins back in!  I had two pins that wouldn't budge on a very old surplus barrel.  Once I did that and switched back to the normal direction, they started to go.  Not easy, but they at least started to move at that point.

Try using a nail  set to get them moving. Good hard steal with a smaller end.

You won't hurt the nail set. Make sure the rest of the upper doesn't wiggle.

Use a good sized hammer and knock the everloving shit out of it. Once it moves then switch to a regular punch. Use a nail set for a finish nail that sinks them so that they can be covered with filler and painted over

I've always managed to do it with the nail set. They have a large squared impact area that transfers more energy...IMHO

Heat it for a short period of time before trying. The difference in expansion of the pins vs. the barrel and block might help too.

I have a 3lb mini sledge in my ar kit specifically for stubborn fsb pins. (usually bushmaster)  That, along with a bigger punch to start the pins, and the brownells fsb block have always allowed me to get the stubborn ones to move.