I built a Bulgarian AK74 on a "bent blank" 80% receiver. It was a fair amount of work to get the rails and mag well trimmed up, but just used handtools and a dremil really.
Then I started running into problems heat treating, I was trying to use a propane torch and Kasenit, I couldn't get the ejector rail nor the fire control group holes to heat treat properly. I ended up buying a pre-heat treated ejector rail from dpharms.com that he had extra (doesn't normally sell them I don't think). That worked for the ejector, no deforming now but the fire control group holes have become slightly elongated, just makes the gun seem sloppy somehow.
I'm going to just buy a finished receiver here locally and rebuild the gun onto that.
The actual process of "building" the kit on the receiver was cake, if you buy a finished receiver there really isn't much to do it the way I did. I did a "screw build" so no fancy tools. My kit had the barrel trunion pressed on already as well so there was no tools needed for this part other than a drill press, and a thread tapping kit and regular hand tools.
Here's a pic on the finished bent blank, but like I said I'm going to strip it back down and rebuild it on a finished receiver, supposedly a local shop has some in stock, need to check that out this weekend.
Here was the kit as I received it:
I'll probably pick up more than receiver and do another build, it's fun and really pretty simple if you do a screw build. If you want do a more authentic rivet build it gets more complex w/ pressing the barrel in/out of the trunion, need a rivet hig and a press or a jury-rigged way of doing it (some slightly modified bolt cutters work well apparently from reading what others have done). And of course if you want to finish a bent blank receiver or bend up a flat that requires more work...
If you just want to get started for cheap Romanian kits (in "excellent condition" supposedly) are available for cheap still for like $100, (
www.centerfiresystems.com advertises those and a bunch of other kits). I think I paid $189 for that Bulgy 74 kit way back when, I think they're going for at least $50 higher than that now, but damn are they nice kits (I think they cut up a brand new unfired gun for mine, I mean it was mint...)