It is possible you could have a warped barrel. I have a 700 ADL Varmint that I bought a few years ago at Dick's. It shot pretty decent. I decided I anted to cut the barrel down to 20". When I went to pick it up the gunsmith told me the barrel was warped and wobbled in the lathe. Luckily the warping started at around the 21" mark. It is now straight and wobble free. Two days ago at the range the best group I had was .307" at 200 yards. This is with the factory injection molded stock that has the buttons at the end that contact the barrel. I have read that in some rifles there is a reason for the buttons making contact with the barrel.
I know this is a 1:12 barrel, but just offering up another possibility.