Need to know all the differences, especially between the trunnions used.

1.  Struts - rolled or not?
2.  Butt - dimpled or not
3.  Trunnions - same or not?  Different hole/pin sizes?

Anyone?  I need to know if I can just swap out the metal buttstock for a smooth-butt, unrolled Russian and keep a Bulgarian trunnion.

Yes, trunions are the same for the AKS74. The trunions are different for the AK74M but can be modified to use.

The russians have plain butts and straight edges. The bulgarians have ribbed butts and rolled edges.  For actual use the bulgarian stock is better, ie less prone to slip and stronger.

Quoted: The russians have plain butts and straight edges. The bulgarians have ribbed butts and rolled edges.  For actual use the bulgarian stock is better, ie less prone to slip and stronger.

Where do you get that info from? Do you own both? Pics?

Quoted: The russians have plain butts and straight edges. The bulgarians have ribbed butts and rolled edges.  For actual use the bulgarian stock is better, ie less prone to slip and stronger.

That's what I thought.  I need to find a proper Russian sidefolder for my AKS-74 clone.

I ordered a Russian sidefolder from K-VAR..

It had rolled edged and the back was ribbed..now I am a little confused

Did I get a Bulgarian folder instead of a Russian..

The ribbed buttplate, rolled edge stocks have been included with many of the Bulgy AKS74 kits, but it is widely believed that they really are of Russian origin.  The same type of stocks with the same/similar proof marks are found on Tula AKSU74s.  Based on photos (including those in the Tokoi book) Bulgaria seems to have used parts and/or assemblies from other countries to assemble their stamped receiver rifles.  Bulgaria probably got the stocks from the USSR and used them on their AKS74 rifles, funtionally they are equivalent with the other style (smooth buttplate, straight edge).

So I guess they're either/both Russian & Bulgarian depending on how you want to look at it.

Russia now produces a straight edged, smooth buttplate sidefolding stock, but it is made for the AK74M 5.5mm (if I remember correctly) diameter pin.  The older stocks mentioned above use a 4.5mm pin (again if I remember correctly).

Quoted: I ordered a Russian sidefolder from K-VAR.. It had rolled edged and the back was ribbed..now I am a little confused Did I get a Bulgarian folder instead of a Russian..

No, you did not these were made in Russia. There are various versions of Russian folders. Many Bulgarian AKS74 were made in Russia and the assembled in  Bulgaria. The ones with the rolled edges are usually Russian. My Krink kits have ribbed buttplate but straight edges and these are Bulgarian

Here are some pics:

So from a Bulgarian kit:

1.  Ribbed and rolled = probably Russian origin

2.  smooth and not rolled = probably Russian origin

3.  Ribbed and not rolled = probably Bulgarian origin

I think you just hit it.

Theres so much sharing/giving away of parts its often hard to tell where  parts originated.  I have had bulgy kits with nonribbed butts with unrolled sides and ribbed butts rolled sides.  And nice pics showing the differences.

Does anybody have a link handy for an online dealer where I can order one of these triagular folders? I was interested in getting an Arsenal AK would would like to fit one to it. Can Arsenal rifles have these installed with relative ease? It would be my first AK, though I am not completely unfamiliar with them (I bought a WASR10 for my little brother for his 18th birthday and have shot it and field stripped it).

Ihnstalling one of these is not for the first timer.  It is for an experianced AK builder.  The cost from a pro is around $225 to $250 plus the stock.  That is just for the stamped one.  A milled Arsenal would be very expensive.