● Inner diameter of Φ6.03mm with a high precision tolerance of ±0.01mm!
● Tighter inner diameter enhances the projectile speed!
● Made from high-strength material, inheriting the technology of the Prometheus 'EG Barrel Series'!
 
This Inner Barrel [250mm] for Tokyo Marui M4 A1 MWS, Type 89 Rifle have had their dimensions refined to improve airtightness, reducing the standard inner diameter from Φ6.08mm to a more precise Φ6.03mm with a tolerance of ±0.01mm. This tighter configuration boosts both BB shot speed and accuracy, making it an ideal custom inner barrel for serious survival gamers.
 
Compatible Models 
Tokyo Marui Gas Blowback Machine Guns:  
- M4A1 MWS  
- Type 89  
 
Warning: 
After customization, always check the joule value and velocity of your airsoft gun. Exceeding the regulatory limit of 0.989 joules under Japan's revised Firearms and Swords Control Law can result in penalties. Measurement values may vary due to factors such as season, time of day, HOP adjustments, and the characteristics of the gun. Ensure your airsoft gun is used with a joule value that allows some margin for safety.
 
Notice Regarding Full-Size Inner Barrel (370mm) Sales Discontinuation:
This product comes in a 250mm size, following the standard inner barrel size. While we considered releasing a full-sized 370mm custom inner barrel that would extend to the full length of the M4A1 MWS outer barrel, our testing from various perspectives indicated a high likelihood of exceeding the legal limit at 20°C, the temperature at which Tokyo Marui guarantees operation.
 
Therefore, we have decided not to release the 370mm version. We apologize to those who were looking forward to a full-sized custom inner barrel. Thank you for your understanding.