PROMETHEUS 6.20mm Delta Stike Barrel ( 550mm ) for Marui M16A1 / A2 / VN / AUG

- DELTA HOP system uses an injection molded part, with 2 lower ridges aligns BB in the center of the inner barrel, forming a 3-point contact along with hop packing for greater consistency. - Low friction material used with enlarged hop opening for better compatibility with high firing rate configuration - 6.20±0.01 mm inner diameter allows greater BB inconsistency,reduces BB bouncing NOTE: Prometheus Straight Chamber Packing and required ( included with first batch ) Recommended to be used with Prometheus Hop Up Tensioner series ( available separately ) Muzzle velocity may drop after installation compared previous inner barrel