I have cleaned many neglected bores of several of my friends. They do not take care of their firearms. I have seen some terribly dirty bores and I have always been able to remove all of the copper with Sweet's 7.62 and JB's Bore Paste from Brownell's. The bore paste will help to smooth out the bore of your firearm. I have seen several of the Remington's with stainless barrels that are rough. You can have the barrel lapped with abrasive bullets. This will eliminate any bore roughness that you may have. All in all 1.5" accuracy is not that bad. You could also try some 200 yard groups to see how large they are. I reload for most of my friends and have ran into some rifles that were mediocre groupers 1.5-2.0" at 100 yards. However, when stepping back to 200 yards the groups didn't enlarge. I have heard some bullets need a longer distance to settle down and shoot. I have a Remington 257 Roberts in a Stainless Classic. When I bought the rifle new it had a rough bore. It would group about 1.75" at 100 with a number of factory and reloads. After about 150 rounds the bore seemed to smooth up and now the rifle will consistently place 3 100 gr. NBT's into a .75" group all day long. I would not like to put 150 rounds through a 300 Win Mag to break it in. This is sometimes necessary if you don't want to have a smith fire the abrasive bullets in your rifle. The abrasive bullets with instructions are availabe if you handload. If you don't handload and all that happened was your groups enlarged did you check to see if the factory ammo is all from the same lot. I had a 308 Model 100 semauto that would group winchester Silver X 150's very well. When I ran out of the 5 boxes of ammo I bought I went and got some more. Groups went to two inches. Behold I didn't buy the same lot number of ammo. I went back to see if maybe these guys had some with the original lot nuber and they did. I purchased one box and went to the range. Groups returned to very good. So lot # can make a big difference. If your gun shot 1" before it should do it again. Probalbly not with the same load since you have had the bedding and free floating work done.