The First Factory 6.03 mm Inner Barrel is a 250 mm precision upgrade designed for Tokyo Marui MWS and Type 89 GBB platforms. Its inner diameter is engineered at ?6.03 mm with a precision tolerance of ?0.01 mm, offering a tighter bore than the Tokyo Marui original specification of ?6.08 mm. The barrel length is designed to improve airtightness, while its enhanced stainless steel construction supports solid BB stability and accuracy. This barrel is compatible with the GBB M4A1 MWS (Tokyo Marui) and GBB TYPE89 (Tokyo Marui). As with any custom upgrade, users should check the muzzle velocity of the airsoft replica after installation and follow the legislation of their own country as well as local field rules.

Key Features

• First Factory 6.03mm inner barrel for Tokyo Marui MWS / Type 89 GBB, 250mm length

• Inner diameter designed at ?6.03mm with precision tolerance of ?0.01mm

• Tighter bore than Tokyo Marui original ?6.08mm

• Length designed to improve airtightness

• Made with enhanced stainless steel material for solid BB stability and accuracy

• Compatible with GBB M4A1 MWS (Tokyo Marui)

• Compatible with GBB TYPE89 (Tokyo Marui)

• Check the muzzle velocity of the airsoft replica after custom upgrades

• Follow the legislation of your own country

• Follow local field rules