20" is perfect for the .223 anyhow. It needs to maintain velocity (preferably over 2700) to destabilize, yaw, and fragment in flesh, so out at range, the extra vel helps out. Doesn't matter, though I guess, since the Saiga is a short range weapon. Sorry, I'm not much help. Take it to the smith for a cut n crown if you really want to - you've got to have a good crown. Should still function though - it's a kalashnikov, not a finicky gas system.