g&p m4 problems

[adamtowery]

Hello techs I'm having a problem with my g&p m4. I was in the middle of a game at east side and the gun started to whin so I stepped of the field pulled the trigger and did not shoot it just spun the bevel ( I checked nothing is stripped) I'm a tech and I can't figure this one out so if you guys could help me out it would be greatly appreciated. Thanks in advance!

[T6e9a]

If only the bevel was spinning, then it, or the spur is stripped. If its an open whizzing sound, then the motor is probably too low.

Pull your upper off and test the gearbox, does the nozzle go back/forth as it should? Or is it stationary?

[luke213]

Well just another thought that could cause it, T6 is spot on. But if the pinon came loose from the I'm not sure the proper name but the drive axle of the motor that could cause a whirring noise with no movement of the gearset. If yours is a round pressed on pinon, versus the D shape with a set screw I'd say it's more common on the pressed on but it's still not what I'd say is common.

As said though if it's not this, or the motor height too low to engage the gears then it's a stripped gear somewhere.

Luke