As you might already know that HAO is a company which dedicate making " RS spec" parts.
So do our MK16 M-Lok handguard.
Some customers might find that their Airsoft AR15/M4 can not use the rail directly.
It's because that some of the Airsoft receiver is more wider then the RS spec AR15/M4 receiver.
BTW, PTW can use it directly as PTW use the RS spec in many way.
If you happened meet it, please follow the manual below for your reference.
When we say RS spec. We mean it.
Oh and we also have new thread option for GHK GBBR and Marui MWS GBBR !