making a full auto AK is a peice of cake. i could do it in 30 minutes with a hand drill. type 7 SOT do it all the time. the hole (pun intended) question of select fire centers around that third axis pin, and the hole you have to drill to insert it. it supports a disconnector, reset coil spring, and the shepard's crook which is integral to the spring.
many kits on the market right now have all of the parts, and could be built legally by an SOT as a full auto on any comercial or homebent receiver. some aftermarket manufacturers are making semi only FCG, and carriers, but the original ones work fine on semi.
i am not advocating that anyone violate federal or local law on any account, but do feel a need to note that most gun boards have at least one expert on hand who will do his best to shroud the entire question in mystery.
of course, if i was hunting big game on the african plain, i would find a decent watering hole, set up a machan (elevated blind), and just wait. some defiant lion would surely walk by after awhile and wake me with a challenging roar.
who pays for this and all of the other gun boards on the net, anyway? nothing is free, unless it's bought with tax dollars.