a complete WTF ! HELP

[Teufelhunden]

right after buying a M4 off here ,
i took it out and started testing it,
nothing is wrong with what so ever,
just took the body off and noticed there is a hole in the cylinder..

i have no idea of make..

heres a pic hopefully,

just want to know what its for

its very perculiar

[The Keeper of Secrets]

Re: a complete WTF ! HELP

It is the port in the cylinder. It's position is designated by your barrel length. It prevents suckback and allows for more healthy gearbox cycling without having to make different length cylinders for different length barrels.

[Teufelhunden]

Re: a complete WTF ! HELP

but its not on my other gearboxs ?
and so if i stick on my m16 barrel its useless ?
and can this determin this isnt a chinese gearbox ?

[The Keeper of Secrets]

Re: a complete WTF ! HELP

It won't be useless in your m16, but the fps will decrease due to suckback.

It may not be in your other gearboxes, they may have longer barrels or incorrectly ported cylinders.

No, ports appear on both chinese and japanese/taiwanese gearboxes.

[Teufelhunden]

Re: a complete WTF ! HELP

ah i see thanks for the help :D