what's this screw for?

[Yakb0]

On my rat impulse, there's a screw poking out of the body, foward and to the right of the vertical adapter hole. It's on the opposite side of the gun from where the VFF hole would be if it was drilled. I've got a 15 degree adapter I can't use, because this screw isn't letting the adapter sit flush with the body.

[Team Chokepoint]

So are you saying its on the left side? I have no idea, its been bugging me for a while. I think that perhaps its there to prevent the VA from rotating. If you look at the stock VA, there should be a groove drilled to accomodate this screw.

[the Ydna]

It's a lock screw that prevents the stock vertical adapter from twisting around. Just unscrew it and it'll be good.