You need to "know" that you have a clean barrel first.

Did you use any copper removing solvent ?

Did you check the bases & rings on your scope.

You need to remove the bi-pod and get on a bench with sand bags at the very least.

Once you know that the barrel is clean, you need to shoot 3-5 rounds to "foul" the barrel.

Then you can shoot 3-5 shot groups, where you have given the barrel a chance to cool down between each shot.

So, as you can see..............you need to start over.