I bought a brand new tikka .300 win mag and shot it for the second time today. The first time I discounted accuracy due to a very windy day and only shot about 12 rounds through the gun. I'm also shooting federal premium nosler 180gr accubonds.
Today I shot and the first group was about 2 inches at 100 yards, shooting from a led sled on a bench. At 200 yards. I ended up shooting 5 times with three rounds in about 3 inches straight across inline with eachother. Between those 3 shots there were two shots that were low and right about 3 inches away.
At 300 yards rounds were not even close and grouped about 12 inches. By this time I'd shot about 20 rounds and I also tried to let the barrel cool down between shots.
I finally gave up and packed it in, thinking I need to start fresh with a clean cool barrel. Upon getting home and beginning to clean my gun, I noticed a pretty heavy copper fouling on the rifleing when looking down the muzzle. I know I need some better copper solvent but I couldn't get it all out, the patches are nearly clean and there's still a significant amount of copper in the bore from what I can see.
Scope is also tight with no movement, as I dabbed a tiny bead of red nail polish where the scope meets the back ring to see if there's any cracking or separation. I had a rock solid rest and felt like I was making good shots but it was all over the place at 300. Is it likely that it's mostly from the major copper build up?
And also, how did I get so much copper build up from so few rounds? I'm not experienced with rifles but this seemed ridiculous. I've got an old 7 mag that I can't see a hint of fouling and I don't have to do much to clean it. For being a new rifle, it sure seems like an awful amount of work to keep it copper free. Is there anything I can do to prevent so much copper fouling?