I just got a Choate Ultimate sniper stock for my Remington 700 ADL. Mine came with this piece inserted into the bottom of the blind mag (see picture). I have no clue what it is for. The receiver would not fit with it in the bottom of the blind mag. I took it out and installed the receiver just fine, but I am wondering what it is for and if I need it. I hate leaving parts out of something like that. Anyone know what it is? Thanks for your input.