First let me say how nice it is that so many of you are willing to take the time you do to help others with problems. I think it's great!
I've had my Saiga 12 for about 6 months and have fired about 250 rounds of high brass slugs and buckshot through it with not one stoppage. However, I recently tried some of the cheap stuff only to find the opposite. It would not cycle at all with ANY type of inexpensive field load. I cleaned and lubricated it thoroughly and checked that the gas ports were clear, but still it either failed to eject or failed to feed on every round. I reviewed this mod and decided to give it a try. The instructions are clear and the images are great, but I did run into one problem I haven't seen addressed. The upper gas block pin on my Saiga would not budge! Not at all! I ruined two punches in the process. Finally, in desparation I tried a pneumatic palm nailer to drive the punch. Worked like a charm! Naturally I had a problem reinserting the pin as well and again the palm nailer came to the rescue. This time I utilized the finish nailer attachment with a non-marring tip and drove the pin right in. I know not everyone has one of these things, but short of a press of some sort there was no way I was going to get that pin out or in. Hopefully my shotgun was unique and others don't encounter this, but if that's not the case, this is a possible solution. Besides, my palm nailer has saved my butt on numerous household projects and everyone should have one!!!!
That's the good news part of this post. The bad news part is that my Saiga is one of the newer two gas port models. No hidden holes to expose! The manner in which the ports were situated matched the description at the beginning of the instructions, so I figured I was fine. Well, since I had the thing apart I figured I'd try opening up the ports a bit. I carefully drilled them with a 3/32" bit. I then reassembled and test fired. All the cheap Wal-Mart ammo except the Winchester stuff functioned flawlessly. With all the negative posts I've read about Wal-Mart's cheap Winchester ammo, I'm not going to worry about it. Now while the other stuff ejects and feeds, it does drop the empties right at your feet. This leads me to believe that as soon as it gets a bit dirty, the FTE and FTF problems will be back. I'm at 65 rounds so far without a problem. I'm going to try some of the suggested bolt polishing methods to see if they help at all.
A couple of other things that worked for me during this Mod that I thought I'd share:
1) A rubber mallet works great to remove the gas block and a plastic mallet works exremely well to reinstall it.
2) In addition to scribing the barrel where in meets the gas block prior to disassembly, if you make an index mark on the barrel and the gas block in a location that will be covered by the forend, you will greatly simplify reassembly by allowing you to easily align the pins.
Well, that's my two cents worth. I hope something here helps someone, because you have all certainly helped me. THANKS!!!!!