I got an Accuwedge clone at a gun show for a buck. Put it in and it tightened the upper/lower, but I didn't notice any accuracy increase. I still have it in the rifle... because I paid a buck for it as much as any reason. It does make the rear pin considerably harder to push out.
Takes out all the 'free play' between the upper and lower, so theoretically... . If anything it will eliminate the slack between the reciever halves which sounds like a pretty good deal to me for a coupla bucks.
Your heart's desire is to be told some mystery. The mystery is that there is no mystery.
i like many dcm shooters use the acuwedge. i agree you will not see any change in accuracy as it does not effect bolt to barrel lock up. but it is a comforting thing to not have your rifle move or rattle. its all in my head but i like my rifle tight. if it feels good do it....pat