https://www.airsoftonlineshop.com/aols-603mm-inner-barrel-brass-091mm-for-gbb-p-1922.html
AOLS 6.03mm Inner Barrel Brass 091mm for GBB [G3-IBC-091] - $10.59 : Airsoft Online Shop
Airsoft Online Shop AOLS 6.03mm Inner Barrel Brass 091mm for GBB [G3-IBC-091] - AOLS 6.03mm Inner Barrel Brass 91mm for GBB 91mm (3.583in) barrel length....