I building a Romanian kit right now. I want to keep the original stock parts so I plan to replace the gas piston as one of the required 6 parts.
Anybody know what size the gas piston pin is? I sanded the outside of the bolt carrier and can just barely make out the pin. I assume that I need to drill the original pin out. I tried hitting it with a punch, but I think it must be peened on the ends. It doesn't seem to budge.
Anyway, what is the best way to disassemble the carrier/piston assembly and reassemble it.
Thanks.

I used 1/8" round stock that I bought from the hardware store.  I took off all of the finish, and found the edges of the existing pin... drill down some until you can punch it out.  Make sure you measure the OAL of the assembly with the old piston in so that you screw in the new one the correct amount.

I believe Pookie's web site has specific instructions, such as what drill bits to use... I'm at work and the port numbers are blocked, so I can't access it from here.

It is peened over on both ends so you will have to drill a little bit to get past the peened part.  Just be sure to center punch the center of the pin so you drill equally.  All you need to do is to remove just a little bit of material.