[RUSTY262]

I'm ready to throw away my tikka stainless laminate 243 because i can't hold an 8" group at 100 yards but since i'm stubborn i need to figure it out. I've checked everything including having taken it to a gunsmith and several gun shops. changed bases, rings, scopes, ammo, shooter, rest, and nothing. Last night i read about copper fouling and put some wipeout in the bore overnight. This morning the patch was navy blue. Would this cause that much inaccuracy? Any advice or thoughts would be much appreciated. The rifle has some sentimental value as it was my first. The first three years i could hold 2inch groups at 200 yards off a bipod.