Well, here's the report. I went to home depot, but only found 1.5" 4D nails; no 2" or 2.5". I bought a box, but figured I would try using a 5/64" 2" allen wrench instead, since it is longer. Then I braced the setup and carefully smacked it with a hammer; no dice. I smacked it a few more times adding greater intensity with each blow, and all I ended up doing was bending my allen wrench (only very, very slightly, since it was almost a perfect fit for the hole, but slightly non-the-less). I called DPMS this morning, and they said the forward assist is within tolerances, since the carrier is not scratched during cycling. So, since I didn't have any luck punching out the pin, and since the forward assist does not impede the movement of the carrier, I think I'll leave it as is. However, since the bore guide is plastic and cheap, I think I'll try to shave one side of it flat, and put the flat side toward the forward assist when cleaning. Thanks for the help, imschur and 98Z5V; I hope I can return the favors someday. :)