How long does an airbrake need to be in an AEG Gearbox?

[Finius 575]

Hey folks,

 

I'm starting to practice some of the techniques I'll be using on my DMR build over the summer and I was just wondering how long an airbrake would need to be in order to be effective in an AEG gearbox?

 

I'll be purpose modifying a standard piston head to fit a screw through it (which will be sealed using silicon sealant), the screw then fits into the inner-nozzle on the cylinder head and provides air braking, which should in theory quieten the gun and also extend the life of the gearbox.

 

Any advice much appreciated.