My Model 10 243 is shooting erratically. Tonight I shot a couple groups and the first shot was way high, probably 2" higher than I thought I had it. Next four were within 15/16", about where they should be. I didn't think I screwed up the first shot but thought it was p0ssible. Let the gun cool, started another group. Same thing, first one was way high, next four were within 3/4 " and where they should be. Let it cool again and shot one more time. Way high again. I believe someone on this board said when a barrel is going the trip that is what they do, correct? It has been quite some time since I cleaned it and one other time I was unhappy with it and cleaning helped but it just had larger groups, not one completely out of the group. What do you think?

I do have a 7MM-08 barrel I could change it to.