Hey Romack,
If you check out the boards, you see differing opinions on riveting vs screwing (it's hard to type that without grinnin'!).
Anyhow, I've done a good bit of homework on this and will be "screwing" my next couple of AK builds. Currently have the parts for (3) projects lined up (an RPK, a Bulgarian '74, and an AK-104 clone) - gonna screw 'em all!
Campy's right, be sure to use fine threaded, high quality screws, torque 'em down well, and use JB Weld on the threads. High Temp Loc-Tite would be OK, but I've used JB Weld on a LOT of stuff and it holds up well for something like this. There's one thing that will mess up JB Weld - grease and oil. Be sure that you degrease the threads well before relying on JB to stick - it won't if the parts are oily.
Campy - on the RPK build, I looked into VEPR receivers, KVAR RPK kits, etc. and just can't bring myself to put that kind of money into it. I got VERY lucky and picked up the last of the kits that XCALIBER had. Mine had a broken "ear" on the front sight, but the bore is VG or better! I'll let you know how it goes!
Thanks to all and Good Luck Romack on your build ~ post pictures!
Jim