Maple Leaf 6.04 Crazy Jet Barrel for GBB Pistol 138mm

The Maple Leaf 6.04 Crazy Jet Barrel for GBB Pistol 138mm is one of the best inner barrels available for GBB pistols or assault rifles.

Maple Leaf's Crazy Jet barrel creates a cushion of air around the bb, which means the bb has less resistance in flight and also gives you a bit more precision than the standard barrel.
This is due to a special construction this inner barrel has.