Madbull Ultimate 6.01mm Tight Bore Barrel 7075 Aluminium (229mm)
7075 Aluminum Construction (even higher grade aluminum than most of real gun and aircraft manufacturers who utilize by 6061 Aluminum)
Suitable for MP5A4, A5, SD5, SD6, AK Beta Series Airsoft Rifle
This is the Mad Bull 6.01 mm Tight Bore Barrel with a length of 229mm. This tight bore barrel is a quick and easy upgrade to get you more power and greater accuracy.
The barrel is set at 6.01mm, as opposed to the stock barrel set at 6.04mm.

For custom upgrade user, you can choose a longer barrel
NOTE: You can always choose a longer Barrel if you have a extended Outer barrel installed