An Encore Barrel that just wont' shoot,...

I picked up an Encore for a nice price with a 308 barrel. The plan was to sell the barrel and start thinking about a GNR pistol barrel. But I got to thinking that its always nice to have a compact truck gun and 308 Winchester is on shelf anywhere that sells ammo. I thought I'd give it a try and if it shoots well at 24" I'd have it trimmed to 2O" for a truck gun. I can't get the darn thing to shoot a group at all. I don't mean it won't shoot a 1 or 2 or 3 inch group,.. its all over the place. You never know what its going to do. I've swapped out everything to known to be good parts. I've tried two scope mounts including a Leupold DD mount. Two of my favorite scopes that work well. I've cleaned the hell out of the barrel. I've tried two bullet weights and three different brands of off the shelf ammo and some of my hand load for another rifle. The muzzle looks good. The frame should be good and can shoot a gnat in the ass with my 25-06 barrel. I guess sometimes you get a booger. I ain't mad. Just feel like blowing of a bit since I've invested a more time than I thought was needed on this one. The only thing I haven't tried it swapping to an different frame. I'll give that a shot and likely put this one back in the safe until I feel like dealing with it again. Right now I have better shooting projects I can play with and I can start thinking about a GNR barrel. Maybe go with a rifle length like a 20" 378.