It is NOT tapered. Just tried it, and it comes out either way. Use a short punch, retains the energy and "whack" way better than a long punch.
I used to only owned the Brownells punch set, and there are times where i had a hack of a hard time getting pins that were fairly easy to come out. I was scared of scratching the slides/receivers etc. One day, my co worker saids get a short set, and voila even the Sig p226 breech ock pin came out with 2 moderate whack. Obviously having the proper support on the back side of where you are hitting helps too.