I plan on only using sub-sonic w/ my gem-tech can----------I guess if I just get a flatop upper and have a bbl setup for it---it really shouldn't be that big of a deal to have a smith set it up for me----the SSK ones are great looking, but too much $$$ for my wallet-----any advice or suggestions would be greatly apprecited
Not that hard to build the upper your biggest challenge/expense is finding the barrel -
Randell of course can sell you one - you can also order thru other vendors SSK being I think one of the most expensive. Mine is ER Shaw barrel found after about 3 months of looking here.
Oher components are easy and assemly requires some few specialized tools. Keep checking Equipment Exchange, and other sights (even E-bay!)
http://www.quarterbore.net/ is good source of info.
as is http://www.silencertests.com
Cheapest prices on dies was Midway -
Other choice is 7.62x39 but magazines are the problem with that choice...
When working up your loads for subsonic start super and work your way down to sub sonic.