Alright, the following is my understanding of the rehreadspacing process for an AK. Please point out any errors,problems, or stupidity on my part.

1: Press out the crosspin securing the barrel in the trunion. 12ton press required.

2: Press barrel out of trunion. 12ton press again.

3: Weld up old crosspin slot in barrell. Arc, Mig?

4: Press barrell back into trunion until the bolt will close on a GO but not on a NO-GO. 12ton press.

5: Redrill crosspin slot and reinstall crosspin.

Is that what it's gonna take? Any advise would be greatly appreciated.

Thank you very much Campybob! I started asking these questions about a year ago, but at that time my assumptions about the process were shall we say...a little juvinile. Since then I i've gotten together what I believe to be the makings of a workable press in my garage. I'm still hashing out the details of getting it working but I'm determined to see this through. Thanks again!

How about using an oversized pin instead of welding up the slot in the barrel? Any tricks to drilling? Specifically, I'm worried about the barrel moving during drilling and changing the headspace. Is the barrel in the trunnion tight enough that this isn't a problem?

Barrel will be incredibly tight...it's isn't going anywhere.

take care,
Tec

After welding up the crosspin groove in the barrel, be prepared for the steel in that area being very hard. A regular bit may only squeel on it, without cutting much, if any.
                               Pete

With regards to the hardened area of the barrell, what sort of drill bits should I be using?
While I'm at it, are there any pics available of the apparatus used to push the barrell out of the trunnion? I'm interested in the part thats actually  in contact with the chamber during the push. Also, what are the GO/NO-GO dimensions for 7.62x39? Thanks!

Depending on how hard the welded area of the barrel gets from the welding, you may need to use a cobalt bit, or possibly a carbide end mill to get a clean cut. Remember you are asking the cutter to engage a hard rounded surface with the receiver hole being the part that is going to suffer if the bit deflects. Far better to reheadspace, drill, and ream for an oversize pin that will be a press fit in a hole that is true, rather than welding. Rec. should be rigidly clamped, true to the spindle of your mill or drill press for this opersation. It's not rocket science, but half assed setups will cause you grief. I'd make sure the headspace is truly excessive before getting into this.
                 Pete

I guess it's time to spill the beans, even if it makes me look kinda dumb.

About a year and a half ago I bought a Saiga 7.62x39 and the gunshow. It was NIB. It looked normal/complete etc. At that time I didn't have the place/time to shoot so the rifle sat around for a while. After a while I decided to change it over to the pistol grip/hicap config. I got the US parts and proceded to change the rifle over. I even managed to get the FSB and gasblock off and back on to install the standard handguard without damaging anything. The only thing I didn't do at that point was install the feedramp. One fine day   I took the gun to a friends place for a quick function test with the ten round mag. WTF?? The rifle wouldn't chamber a round. At that point i took a close look at the bolt. Looks to me like it's a .223. In a 7.62x39 rifle. JEEEEEZZZZZZ.... Apparently sometime after the factory some bubba had two saiga's apart on the same table and swapped the bolts by mistake. I got my hands on a Bulgarian 7.62x39 bolt and a "fat tail" carrier to go with it. Unfortunatly when that bolt is in battery with a round in the chamber there is 1/8-1/4inch of back and forth play. Possably the loosest headspace ever recorded on an AK. And dangerous as hell.
I've moved a couple times since I got the rifle so of course I lost the reciept. I can't even remember what the vendors name was. I called EAA corp. but they won't say word one until I send them the rifle to look at. Since it's not in original config I have my doubts about whether they will fix it or not. So here I am, the victim of my own stupidity for not checking the gun more carefully when I bought it.
As I see it my options are: Ship it back to EAA and hope that they fix it without charging me much. If they won't fix it I'll either have to send it to a smith and drop $75-$100(various quoted prices) to have him make it right or finish building a press and hope I can fix it without destroying the thing once and for all.
Sorry for the long post, but thats my story. And it's a whopper.

Quoted: I guess it's time to spill the beans, even if it makes me look kinda dumb. About a year and a half ago I bought a Saiga 7.62x39 and the gunshow. It was NIB. It looked normal/complete etc. At that time I didn't have the place/time to shoot so the rifle sat around for a while. After a while I decided to change it over to the pistol grip/hicap config. I got the US parts and proceded to change the rifle over. I even managed to get the FSB and gasblock off and back on to install the standard handguard without damaging anything. The only thing I didn't do at that point was install the feedramp. One fine day   I took the gun to a friends place for a quick function test with the ten round mag. WTF?? The rifle wouldn't chamber a round. At that point i took a close look at the bolt. Looks to me like it's a .223. In a 7.62x39 rifle. JEEEEEZZZZZZ.... Apparently sometime after the factory some bubba had two saiga's apart on the same table and swapped the bolts by mistake. I got my hands on a Bulgarian 7.62x39 bolt and a "fat tail" carrier to go with it. Unfortunatly when that bolt is in battery with a round in the chamber there is 1/8-1/4inch of back and forth play. Possably the loosest headspace ever recorded on an AK. And dangerous as hell. I've moved a couple times since I got the rifle so of course I lost the reciept. I can't even remember what the vendors name was. I called EAA corp. but they won't say word one until I send them the rifle to look at. Since it's not in original config I have my doubts about whether they will fix it or not. So here I am, the victim of my own stupidity for not checking the gun more carefully when I bought it. As I see it my options are: Ship it back to EAA and hope that they fix it without charging me much. If they won't fix it I'll either have to send it to a smith and drop $75-$100(various quoted prices) to have him make it right or finish building a press and hope I can fix it without destroying the thing once and for all. Sorry for the long post, but thats my story. And it's a whopper.

The Bolt lugs on the 100 series(which your saiga is) AK bolts are longer than the bolt lugs on the fat tail bolts.

You need a new trunion or the correct bolt.

If you just move the barrel back that far, you will put other assemblies out of configuration.

You are in way over your head, contact the manufacturer or send the rifle to a reputable smith.  Don't dig your hole deeper.

/Quote
You are in way over your head, contact the manufacturer or send the rifle to a reputable smith. Don't dig your hole deeper.Quote/

Heavymetal, you are no doubt correct on that.
The hole was getting pretty darn deep, and threatening to cave in. I'll send it back to the source, and hope for the best. Your advice is appreciated and taken to heart.

My first advice is to contact the importer(EAA  IIRC) and be 100% honest, throw yourself on the mercy of the court and hope for the best.  They might let you off the hook easy.