M4 rebuild help

Discussion in 'Gun Building, Modifications & Repairs' started by airsoftplayer14, Nov 11, 2012.

  1. airsoftplayer14

    airsoftplayer14 New Member

    I'm rebuilding my g&p m4 so it shoots around 420fps and a rof around 25 to 30 bps max with a 9.6v battery. All I need to know is what gear set or gear ratio would be suitable for this build also a nice piston would help and motor.