I am very slowly building another AR for the 7.62x39. So far all I need is a barrel and bolt and buffer tube and every thing that it needs. Is spending money on a real good spring and fancy buffer with different weights advantageous?. I will be doing no hotrodding. I want a good cast boolit chucker and as light as I can keep it. I also think an adjustable low profile gas block would help with the tuning. Any thoughts to this build? Is carbine a good place to put gas block for this cartridge shooting lead?