i have been doing some research on a 6.01 tight bore for the m700. but i have a big problem...i cant seem to find a accurate length. i keep getting mixed answers. like i find that some says to use a M16/AUG barrel, others say PSG1, or 600mm, 590mm, 650mm. and i also heard i need to do modifications so the barrel fits. so i was hoping to clear this out so i cant get done with this upgrade.