thirty06,
In the early 1980s I practiced with and shot several military style matches with a Remington semi-auto. It started out a very accurate rifle and went to hell in about 2200 rounds. The usual screw tightening to the indices I had on the firearm screws with model paint no longer kept its accuracy up to par. Additionally, a very thorough cleaning did not help. I sent it back to Remington and they tuned it for free and sent it back, whereupon it was accurate again. They also sent a letter that stated it was not made for the type of heavy use it was getting in the military type matches it was being used in. So, if you have shot this rifle heavily, it may be tired as my rifle was, and perhaps a trip back to Remington is in order.