I have not been into weapons since the mid 90's but I did purchase that 5 dollar part before mentioned that converts the weapon to full auto. It was cheese ball to say the least. With a 30 round magazine in the ak it did not release until the clip was empty. Otherwords I had to hold the 7.62x39 mm solid until it was finished firing. Military grade full autos will cease firing when you release off the trigger. My grandfather had alot of land and I was shooting it in the back part of it when this happened. I purchased the part out of a small catalog from a place called Tapco in Georgia. I would be careful buying gimmics as a weapon can be deadly in untrained hands or when not working properly. Especially something with the ability to rapid fire.
I was reading a magazine on military tactics and I believe that the United States military no longer issues full auto small arm weapons to individual soldiers. They now issue the tri burst feature and semiauto only as muzzle climb and recoil is excessive in full auto. It was stated after many test they found that it was a waste of ammunition to use full auto. They claim with the right tactics the tri burst still offers cover fire and increased accuracy. Also virtually eliminating the wasted rounds or excessive wear on the weapon.
Be careful with that, posession of a DIAS and a weapon that can use it is classified as owning a full auto! If you're looking for info on NFA stuff, check http://www.cs.cmu.edu/afs/cs.cmu.edu/user/wbardwel/public/nfalist/nfa_faq.txt
Be warned however, that your rights DO vary from state to state. For instance, in Illinois I can't own any NFA items at all.