Had a local gunsmith shorten my Polytech M14 clone. He fitted a Vortex style flash hider and I provided the gas block sight. He also touched up the trigger, accurized the gas system and checked all the tolerances and timings, total cost was $289, the gun itself is quite new and cost $500.
Polytech is one of the factories that exports under Norinco, but now has it's own export permit. They make a nice product
Historical sidenote, they first made M14 clones as part of a plan to supply communist filipona rebels but never went through with it.