Mine is loose also. There are three trains of thought re the barrel lug. One says to remove it entirely, a second says to lock it in place with a set screw, and a third says it should float freely. I'm in the third camp.
Mine seems to shoot best with 15 inch pounds on both screws. Having said that, all the front screw does is hold the lug in the stock, how much force it exerts on the barrel dovetail is anyone's guess. I think very little, ideally it would allow it to float in the barrel.
I put an epoxy "pad" about the size of a quarter between the barrel and the forearm on my Varmint, directly above the sling stud. The intent is to reduce stock flex when using a bipod. It reduced the vertical element in my groups by probably 30-50%. If you do that, wax the barrel channel first so you can remove the epoxy if you want to. Also apply a couple coats of shoe polish to the barrel first, the same as when bedding an action.
Intersting, thanks for the info. I may try this...
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