TK twist barrels are made for Japan where the LAW prohibits people from owning airsoft guns that fire over 328 FPS on a .20 BB (1J).
There's alot more you can do if you don't have those restrictions.
Also, about the comment on how I used my SVD;
I used it as both a sniper rifle and a DMR. It was equipped with a MOSFET and an 11.1 25C LIPO battery.