Type 1 chrome Bore-Up cylinder

     Type 0 chrome  Bore-Up cylinder

The cylinder is made of brass. It is covered with chrome and its inner part is additionally polished. This influences the operation of the piston’s assembly which is more efficient due to the fact of the reduced coefficient of friction. The cylinder is designed to fit the M4A1/SR16 and other replicas that are equipped with inner barrels that are from 360 mm to 450 mm long. The cylinder has got an increased diameter what means that it can be used only with appropriate cylinder heads and pistons (Bore-Up)