I have a GSG 5 that has 4 screws at the front of the receiver, it has a manuf date of July 09. This screw basically completes the four quadrants at the front, but does not go all the way thru the receiver housing like the other three.
Does anyone else have this?
I got the screw upgrade kit but have not determined if it includes this additional screw.
It is a set screw to keep pressure on the barrel.
That's my guess.
Is your gun a Gen 2? Mine is and has the 4th screw. I've seen some with only 3 but those seem to be Gen 1 GSGs.
Yes it is a gen 2, I sent ATI an e-mail about it and they said that it was a change in the design to better secure the barrel.
All of the photos and posts I have seen so far have only been the 3 screw version.
I got the replacement screw set and had to make sure I had all of the screws.
I have a Gen 2 GSG-5 SD and mine also has the 4th screw. It is in fact a set screw.