Well, doing my first build, and things were going pretty smoothly, until the dreaded taper pins on the front sight. I couldn't find a big brass punch anywhere, so I went after them with the punches I had. After mangling those (and a bit of finish on the front sight base), I finally got the damn thing apart. I installed a YHM free float which was the purpose of this whole adventure - hopefully the barrel nut is torqued enough, the instructions said hand tight, then tighten to the next hole.

Now the real fun starts - I have beat the crap out of the taper pins to get them back in. One is seated, the other just will not go all the way. Are all taper pins like this, or is this just the way BCM's fit?

I think I might design a tool that works like a chain breaking tool to get these pins in and make millions (okay, maybe a couple hundred bucks) off of frustrated arfcommers

P.S. What should I use to touch up the finish on the front sight base?

They're real easy if you have the right tools - like a taper pin punch and front sight bench block.

lol @ your taper pin fun, been there, done that on my FN barrel. you gotta get them back in just right, or your FSB will be canted. and by just right, I mean it has to be perfectly the same way they came out, because there is a nice little jig that is used when a barrel is mated up with a FSB using taper pins.

rots of ruck

Make sure you use a Cupped punch to remove/install pins.  A flat punch will peen the ends of the pin, creating a "Rivet".  You can use a small grinding stone and a Dremel Tool to add a Cup to the end of a flat end punch.    

Make sure you are hitting the correct side of the pin

Thanks for the tip on creating a cupped punch - I was kinda wondering about that. Didn't know about the pins being a one use item.

Quoted: Unless they come out clean and easy, I toss em.  They are cheap. Removal secret, get the special punch at brownells and pre-soak for days in Kano Kroil.

Kroil rules.