Thread: Turning a barrel contour down

Originally Posted by Woody

I have read accounts by competition shooters describing having to fire in the order of 20 rounds after cleaning copper residues from barrels before reliable grouping returned. I have had a similar experience myself. Any comments on this?

Yes, that is a common thing. Barrels perform best when they are at a certain level of fouling which varies from gun to gun. It always takes freshly cleaned barrels a few shots (usually 2-3) to settle to consistent grouping. Once the fouling gets to a certain level it stays that way for a great many shots, giving a consistent friction loading on the bullet. Target shooters always fire a few fouling shots from a freshly cleaned barrel before shooting for score. From a hunting perspective, where sub MOA performance is not needed, then it is not much of a problem.