Yeap buy the time you buy a sunomi barrel that is the right size then buy a sleave that fits it and then find a way to get it attached ( I dont recomend welding on barrels) then buy some dodad to make it longer and legal and still have to turn it down to fit all the other stuff you can likely for a few more bucks get a barrel made and be able to add muzzel attachemnts to it as it will be long enough to start. Now if you had a all the stuff to do it including the barrel then it migt be differant. Sunomi kits used to be $25 and that is why so manmy guys bought them for parts. i have a few still my self. the other way to go is build this as a pistol and then you dont need it to be 16".If I went with a barrel black right, since I don't have a lathe or enough experience with them to use one what do you think my best bet is ? To get the barrel, gas block, rear sight block, handguard retainer and muzzle break and send them out to someone with a lathe and have them turn the barrel down for all the parts and to fit the front trunnion too ??
Honestly you might want to consider building your kit as a traditional 7.62x39 to get the feel of what is involved in all of this. doing a 9mm blow back as a first build is going to be tough with no machinery. Im not saying you cant do it but your looking at a lot of obsticals. have you seen the bolt /carrier assemblys already made for blow backs?? it might be worth it for you. they replace the original bolt and carrier.