I just tightened the barrel grub screws that came loose. I noticed a third, threaded hole at the front of the pic rail, no screw in it. Can someone tell me what that hole is for?
Avenge x, cs4 compressor and a gold tuxing filter from Amazon are all ordered. I already have scope and rings. Can anyone tell me it there any fittings or adapters I may need? Or anything else?