Hi Folks, New to LRH and have a general question about the 7mm Mag caliber. Bought a new factory 7mm Mag barrel for my TC Encore and noticing my group size deteriorating after about 30 rounds through the barrel. The group change is so extreme, from less than one inch to over two an a half inches, that I thought my scope bases had loosened. After I had cleaned the barrel with copper remover the accuracy returned to normal. I have never experienced this with my 223 or 308 barrels with so few rounds fired. Is this common for this caliber?